I don't know how to define the line between legitimate and illegitimate opinions, but I suppose most of us agree that such a line exists and I argue that this sub should be well behind it.

The problem is that everyone's line is different. What you consider to be morally right I may not and you are assuming that reddit should take your side over someone else's.

Even if reddit does side with you, which is most likely, why should it only censor these types of subs and not every other one that does not make the site more marketable to a general public? Doesn't that hurt the rest of the community by making them an echo chamber as well?

Reddit presents itself as a community, and one of the responsibilities of a community is to exclude certain types of behaviors to protect itself and its members, such as being openly racist[1] (even when provoked).

Reddit presents itself as multiple communities. Theres a clear distinction between the people that frequent the default subs and smaller ones, feminist vs mra, racist vs tolerant, pizza vs cake etc. If reddit is represented as one community overall that's an error with whoever is representing reddit, not in what reddit allows.

And again; saying that we need to censor certain behaviors to protect ourselves/other redditors only sounds nice when you agree with what's happening.

A lot of people appeal to arguments regarding "freedom of speech". These arguments are all irrelevant as I never argued that anyone's freedom to express said views should be impeded. I was merely arguing that Reddit should not allow it. An online community has the right to forbid certain behaviors which are (and should be) legal. I never said "the internet" should not accommodate these opinions as a whole, and if these guys really want a community they can form one elsewhere, where their poison doesn't trickle across communities occupied by, among the rest, impressionable youth.

When people are bringing up freedom of speech they aren't speaking in regards to it being a law but of it being a standard of equality and morality that many of us hold in high regard. To openly support censorship of other ideals that insult our own is to promote the idea that we should not have freedom of speech.

And you have stated, multiple times, that they should go somewhere else if they want to voice their opinion. I'd like to ask, why they should be the ones to leave and not you? They formed their own community in their sub and kept to themselves for the most part but because you web-surfed in the wrong direction or something and found them now they have to leave?

Also, that "impressionable youth" thing is not a reason to ban anyone. I'm sure they feel the same way about your views being exposed to "impressionable" kids. People have tried to use that as a reason to ban homosexuality, protest, and free speech. Saying that it's a problem because young people may discover it is saying that you do not have enough confidence in your own position to convince them yourself.