Sounds a silly question, but stay with me.
I'm 30, and remember at secondary school the bullies were generally popular. Mocking, being verbally abusive and bullying vulnerable, disabled, lonely , isolated kids was generally laughed at and seen as positive and funny by their peers.
When I went to uni , I was allocated a place in halls with some "mean girl" queen bees, who would openly discuss how they would leave out/ ostracize / mock those they felt were beneath them, ( examples included hiding the entirety of one flatmates pots and pans as she cried in her room as they said they couldn't live with her next year. deliberately laughing at "dancing/ pushing," a geeky girl out of the circle dancing in clubs , "embarrassing to be seen next to her ," and laughing and supporting an older student who had taken a geeky younger students virginity to send her very nasty texts mocking the sexual encounter etc).
I was in a bit of a unique position as I was slightly older than the uni students involved, ( I'd started uni later due to physical ill health), so when I asked them why they did this , they laughed and said that's what everyone is like at 18-21.
Now I've got older, I've noticed such blatantly nasty behaviour wouldn't really fly in environments of over 25's, ( e.g most of the mum's groups / playgroups I've been to have been very welcoming).
Certainly mocking / laughing and behaving in such a nasty way wouldn't be celebrated.
So is there a kind of cut off where spiteful/ mean-girl behaviour is no longer cool.