> Taunting you even when you're at home?

This might be a European take, but we used to actually visit each other. When I was a kid, you'd only rarely hang out at home. You'd mostly be out with the other kids at a playground, someone's house, or downtown.

Keeping people out of those "shared but private" spaces was part of the bullying. In that sense, a shared Facebook groupchat isn't any different.