> In my estimation, the larger and broader a group is, the more it'll approximate human culture and interaction as a whole. It shouldn't be a surprise when the negative parts of those things (e.g. war, strife, hatred) emerge, just as much as the positive things (peace, fellowship, love).

Given how vicious and downright nasty politics can get in incredibly homogeneous small towns/organizations/communities, I don't think the size of a community has all that much to do with this.

As soon as everyone is not friends with everyone, people start behaving in incredibly shitty ways. If the community does not police that behaviour, the resulting interactions become quite visibly toxic.

If the community does police that behaviour, then they are still toxic, but in a less-visible manner.