Bullies Are Full Of Fear

People with domination/bully issues typically don't stand up against bullies, they don't stand up FOR other people against bullies, and they attack people who they think are NOT likely to smash them back down.
They attack, disrespect, and "blow off" those they believe to be less powerful than themselves either socially, physically, financially, or politically, and ALSO those who they think will NOT retaliate because of values and ethics.
(That's why they usually attack/blow off/disrespect/slander those in their own family, or those they've gotten to know. They have gauged the person to be either unable or UNWILLING to retaliate against them.)

Those they actually FEAR, however, either socially or physically, they will continue to treat with the most courteous "respect and civility", regardless of the person's actions or attitude.

"Bullies" don't know the difference between respect and fear, or that there even IS a difference.
Most bullies think that the only reason a person does not retaliate against them is because of fear; they don't understand "values" or "empathy", so they can't factor them in.

Tragically, their children often miss out on learning the difference as well, because they're learning from the adults in their lives.
If children don't ever come across adults who are willing and able to guide them in ethics, values, and boundaries, their chances of ever learning are next to nil.