[ruytlm]

>Also, finding other people who enjoy talking about cars or writing fan fic doesn't have this sort of harmful in-group/out-group dynamic.

Purely anecdotally, but I beg to differ. There is more than a little bit of tribal hostility on e.g. Tumblr around various fandoms.

To me, the real issue is that surrounding yourself with like-minded people only teaches you to interact with people you primarily agree with and are comfortable with, rather than the more valuable skill of interacting (civilly) with people you disagree with.