Reddit has the best content moderation of any of the big social sites. Because it's mostly done by transparent votes. I've always found reddit, with a curated approach, to be the most positive place on the internet other than group chats with friends.

honestly pretty much all of the comments I’ve had on my posts have been well reasoned and without a trace of childishness or mutiny!! Obviously people have different opinions to mine but they never get personal in the comments! It may just be the communities I’m in but I’ve never been disgusted by a reddit comment I’ve seen on a post I’ve made :) but i do hear a lot about reddit being a cesspit hahaha