I've been a redditor for something like 4 years. I've read thousands of complaints about Nazi mods banning people they disagree with. Upon closer inspection, I've found the vast majority of those who were banned deserved it. In only a handful of cases have I seen mods who legitimately were trying to censor opinions they disagreed with.

People have a tendency to hide behind the principle of free speech as if it were all-encompassing and omnibenevolent. It isn't. Just because you have the right to speak your mind doesn't mean you have the right to be heard. Low-quality contributions can and must be suppressed if the level of discussion in a community is to remain high.