In real life, you can—to an exent—choose your community and who you hang out with. Online with social media, that’s much, much harder. This is a good video (“Something Strange Happens When You Trace How Connected We Are”) from Veritasium, and if you’re busy, that link takes you to the section on how the classic Prisoner’s Dilemma works when you add in network effects. Game theory tells us not to feed the trolls.