I'm ok with forcing the KKK underground.

The problem is thay it's not even as extreme as the kkk, if your opinions don't mesh with the current progressive groupthink, you will be downvoted, ignored, and bullied.

The same happens to a lesser extent on HN, but without the bullying.

The end result is content that leans in only one direction because everyone else has been silenced, they don't bother posting, or they left.

The irony is that this behavior is exactly what progressives have claimed to be fighting (discrimination and online bullying)

Edit: haha, the ironic downvoting happened fast.

Their private areas of the internet, namely Stormfront, predate Reddit. Before Reddit allowed racists and moot created /pol/, they didn't have a real platform to spread their propaganda, so you had to look pretty hard for sites like that. If they only had private forums, events like the Charleston shooting wouldn't have happened.

Moderation helps weed out the spamming, trolling, and general trash-posting that can quickly crowd out any real discussion. That stuff lowers the value of the site for anyone other than the basement-dwellers, and therefore lowers the value of the site as an advertising platform. The only reason the site owners would care about the KKK is in terms of whether they increase or decrease the total number of clicks.