The “free speech” aspect of this is largely nonsense. Reddit is not a public utility or a public square; it’s a privately owned space on the Internet. From a legal and (United States) constitutional point of view, people who post on Reddit have no “free speech” privileges; they have what speech privileges Reddit itself chooses to provide them, and to tolerate. Reddit chooses to tolerate creepiness and general obnoxiousness for reasons of its own, in other words, and not because there’s a legal or constitutional reason for it.
Personally speaking, when everything is boiled down to the marrow, I think the reason Reddit tolerates the creepy forums has to do with money more than anything else. Reddit allows all those creepy subreddits because its business model is built on memberships and visits, and the dudes who visit these subreddits are almost certainly enthusiastic members and visitors. This is a perfectly valid reason, in the sense of “valid” meaning “allowing people to be creepy isn’t inherently illegal, and we make money because of it, so we’ll let it happen.” But while it makes sense that the folks at Reddit are either actively or passively allowing “we’re making money allowing creeps to get their creep on” to be muddled with “we’re standing up for the principles of free speech,” it doesn’t mean anyone else needs be confused by this.
Gawker, Reddit, Free Speech and Such – Whatever. Read Scalzi’s whole post. READ IT.