He/She Won't Stand Up For Me

Beware of a friend or partner who does not stand up for you against the disrespect of others.

This is a red flag; it indicates either Narcissism, or it indicates Codependence. Obviously if they're a "Narc", they aren't standing up for you because they LIKE it when others disrespect you. They're just letting someone else do what they want to do, and are probably hoping they won't get noticed that they're not doing anything about it. However if they're Codependent, they may be so used to being surrounded by manipulative Controllers that they react to disrespectful or abusive behavior by sitting down and being quiet.
They may be conditioned to NOT stand up, because they fear reprisal, consequences, retaliation, and this fear may be the only reaction they have to domination and disrespect, especially toward someone else.
"Fight or flight" is not really a complete description of the instinctual reaction to a threat (which includes disrespectful speech and actions, such as treating a person like they don't exist or are "lesser"). "FREEZE" is the third component that is frequently left out. So it's really "Fight, Flight, or Freeze". When your friend, partner, or family member has the reaction of doing NOTHING when someone treats you with dishonor, and especially if this is accompanied by them wanting YOU to do absolutely nothing as well, they may be having this Freeze reaction.
They probably don't realize it's a "reaction", and will most likely rationalize their feelings and their desire for you to be quiet about whatever happened, saying things like "don't rock the boat", or "don't make a big deal out of it".
Actually, not doing anything IS what makes it a big deal. One does not need to have some kind of Histrionic Fit when standing up for someone against disrespect, and in most cases, direct confrontation is not even necessary. However, pretending no one noticed the behavior IS the same thing as condoning it and encouraging it.
Defending the disrespectful or abusive person is an even bigger flag that indicates either Narcissism or Codependence. Which one it is may take further observation, but acknowledge the flag and reinforce boundaries before making that distinction or taking any action. 
Further, the family member or friend who disrespects a person's partner, friend, relative or child IS showing domination behavior and disrespect to BOTH people, not just to one. The dishonor of the relationship between two other people is a very common behavior found in those with Narcissism, with or without another "co-morbid" disorder or mental illness. The reason is simply envy, and fear of losing influence and control over a person.

Narcissists will often try to destroy the relationship between someone they feel ownership toward, even if they aren't very "close" to that person, and a new person such as a love interest, or another family member.  

Their desire for control and ownership over others is part of their disorder, and they will do all kinds of things to prevent the loss of one of their possessions. They can't handle the fact that a person they feel like they own might have a relationship that might take them away, even for a moment, from their control. They also fear that this other relationship will expose them for what they are, and the object of their possession will realize they have been being manipulated for however long it's been.

The most common  incidence of this behavior can be seen when someone finds a new love interest that's apparently serious. The non-Narcissist friends and family will be happy for the couple, and try to get to know the new person, welcoming them and including them warmly. They will of course be interested in the person in a positive way, and they will try to make them feel comfortable.
Narcissistic "friends" and family members, however, will of course feel threatened by this new person. They will often try to drive out the new person with all kinds of behaviors that resemble childhood antics on a school playground, such as ignoring, making snide or sarcastic comments, trying to make them feel unwelcome and uncomfortable. The Narcissistic friend or family member will often try to make the person they feel like they "own" turn against their love interest by pointing out "flaws", by magnifying anything they can use as "flaws", by painting them to be a bad person who's out to hurt or use their "owned" person, by excluding them from activities and events but inviting their "owned" person, by setting up their "owned" person with other people or pointing out other people that would be "better" for them. Narcissistic friends and family members will especially do this if they are worried that the new person can see them for what they are. Unfortunately it often WORKS, because the person is so entrenched in this group and their behavior that they don't realize what's going on, and they can lose what would have been a fantastic relationship.

This same behavior can be seen among family members as well, and in platonic friendships. Anywhere that a Narcissistic person feels ownership and control over another person. Children often do this with adults, pets, and one another, however healthy children grow out of this stage. Those who develop Narcissism do not.

Those who have become acclimated to an abusive/ hostile/aggressive/manipulative environment, especially if they have been the target of direct abuse, can develop Codependence that looks a lot like Stockholme's syndrome, but on a broader level. WHOEVER the "bully" person is, that is who they will "respect", although it's not really respect, it's a conditioned response to Domination Signals. Fear of getting SEEN, of getting SINGLED OUT, of getting attacked, humiliated, slandered, ridiculed, LEFT OUT, etc. is what's really behind this "RESPECT", but this awareness has been buried by the subconscious. It can feel instead like security, acceptance, even like a parental relationship, or like acceptance as a member of an elite or exclusive club over time, so it can be very difficult for a person to break out of the mental conditioning. Atmospheres such as this are easily seen from the outside, and often heavily defended from the inside, including by those who are oppressed within it (Stockholme's Syndrome -like behavior).

In regions, societies and cultures where this is widespread, children often grow up to mimic the adults in some kind of "Hierarchy" that was created by this domination behavior, often originated by criminals and the domination-obsessed who sought control over others in past generations. Such children will become confused early on when they realize that either they, or those they care about deeply, are being treated with dishonor and disrespect for no valid reason. This confusion eventually, unfortunately, often gives way to the desire for acceptance by the group, which is common to most primates, and especially Humans. So if it means being accepted, one will often start to give in to getting treated as a sub-class being, as if they are secondary to others even in their own family.  Or they will give in to allowing others to treat those they care about and respect with this dishonor and disrespect by others, like they are a "lesser" being within the group (such as one of their parents, siblings, or friend; and later, their own child and their partner.)

This is tragic, obviously, but happens in many human cultures and societies all the time. It causes great consequences in the mental health of the entire group, and serious rifts between people. It destroys relationships and families from within, and it undermines the business economy, driving out good business and bringing in black market dealing, governmental corruption, street crime, and sex "trade". There is openly practiced prejudice in such areas, and a large incidence of nepotism and cronyism in business and government. Schools are directly impacted, and it shows dramatically in the performance and behavior of the students.

Unfortunately, the problem grows exponentially, sometimes until the region's economy is completely destroyed, or the rights of citizens are so imbalanced that the economy resembles a medieval kingdom with very wealthy on one hand and struggling serfs on the other, but nothing in between.

On a larger scale, this problem drastically slows real progress which is clearly demonstrated throughout history; the only things that seem to "progress" in such atmospheres are weaponry; other things creep along slowly, or actually slide backward. It may be difficult to make the connection between "social hierarchy" and halted scientific and civil progress, but that difficulty is actually a symptom and result of the same social conditioning, believe it or not. They are intrinsically intertwined.

(Modern examples of that halting progress are fuel, energy, and fuel efficient motors.)