I wish I could remember where I found this, but there was a fascinating read a few years ago that helped me understand the social impetus behind teen girl behavior. In essence, they’re learning how to build communities, but some of that is expressed in gatekeeping/negative ways.

Unfortunately, that bullying is amplified to incredibly toxic levels online.

Anecdotal, but as a kid from the 90s it always felt like kids were really abusive/toxic and there were always power dynamics going on.

Kids are brutal. I'm not sure if it's like that everywhere but it sure feels like a universal truth.

Related: does toxic feminity exist?

I think most would say no, but who knows

I think you could find many people who would agree that gender roles are toxic. Who is responsible for them is another question

Perhaps both teen culture and social media contain toxic aspects? It is not mutually exclusive.