Sometimes it's not socially acceptable to be mean or even assertive. If we can walk away and be in control, yeah, fuck you is the best option with an abuser. But sometimes we need help and in those situations may also be judged or called bitchy by others who we need to survive.
Women are almost always allowed to be nice, and sometimes that is the only thing we are allowed to be. There are all sorts of names for women who aren't nice, even in just brief moments, bitch, Karen, etc.
Sometimes men are considered door mats for being nice, and are only encouraged to be angry and horny as their acceptable emotions. Even those are in check. Men often aren't allowed certain emotions in certain situations. Women are always allowed to be nice. So sometimes we result to using that to survive. I've long learned the power of fawning. People tell me I'm the expert of kill 'em with kindness.