Its "real" freedom of information, without many of the mechanisms that larger society uses to fight back against it. Instead it is just ignored and left to fester and grow until it pops into the public forum at the point where huge efforts are required to fight it. I feel like the internet is a great way to get differing views out, but not a great way to build any cultural agreement.
CNN and Infowars have the same number of subscribers on Youtube. Now, I'm no fan of CNN, but Infowars is a unique kind of gross in my opinion. To the extent that subscribing to a youtube channel connotes social value, apparently the world has decided that Infowars is approximately equal in value to CNN.
Most people view CNN through TV or CNN.com; I suspect a much greater proportion of InfoWars's content is viewed through YouTube.
Reddit is among the most widely-used websites in the world -- 7th, by Alexa's rankings. Reddit lives up to its motto of being the front page of the internet.
Imagine one of the top-10 newspapers in the United States were occasionally publishing stuff from /r/The_Donald on its front page, and had content from various hateful sub-reddits a few pages back. You could argue that this imaginary publication harms society.
Of course, Reddit is not the New York Times. So different standards apply. But the argument that Reddit -- and thus its administrators policies -- may be harming society, seems to hold some weight.