The problem isn't with people liking the bashing posts.
The problem is people making those posts.
A lot of people say that things on the internet shouldn't matter. That if someone is being an nerf herder, you should just 'grow thicker skin and deal with it'.
In my opinion, that's bull. We wouldn't have to have thick skin if people weren't assholes. Some things, of course, we can't stop. There are some offenses that can be written off. Sometimes the 'victim' really is the wrong one. 'Course, that doesn't mean every victim is just whining over little things.
Asshats are asshats. No matter the context.
People liking asshat posts aren't asshats themselves. Well, they can be, but it doesn't make them karkweasels.
However, someone's idea of humor can make them a bad person.
For example, I'd never want to be friends with someone who laughs at rape, suicide, racism, sexism, misogyny, abuse, or anything like that. Making fun of mental illnesses is also a big one.
Alas, there is no solution to this. People will continue to be assholes. There will always be people who will frustrate you.
I say let them like passive-aggressive (or plain old aggressive) posts. At least that'll help you know who you want to deal with, and who you just want to stay away from or distance yourself from.
*shrugs*