Shout something long enough and hard enough, and people will widely begin to believe it. Wired doing what they just did here is at least part of the reason that perception exists. Certain rabble-rousers within the community itself are another.
It's an accusation. A smear. For it to be otherwise, there'd need to be proof, something sorely lacking from this meme.
EDIT: Honestly, looking at everything that happened a few months ago with the blackouts and multiple events surrounding Ellen Pao, it's nothing but embarrasing how vocal some communities can be that cause many people there for good reasons to be silenced and unheard.
Well duh, hence why fatpeoplehate got banned and shitredditsays stays because they're pretty much the same subreddit, except the latter actually breaks the rules.
Except for that time that fatpeoplehate doxxed the staff at Imgur on reddit when Imgur no longer tolerated FPH posting images of fat people to laugh at on their servers.
Context is important.
You can also just do what everyone on reddit does: label them a SJW, a term with near-limitless utility on reddit, and dismiss them. Anyone with a mind toward social issues will be labeled a SJW in short order, and for some reason that particular accusation resonates with much of the reddit community. This is all just my experience, of course.
That is an excellent argument for not including those subreddits in the default home page (for users who are not logged in) or /r/all.
But you can find offensive things, or things you don't want your children to see, on just about any site (also, yes, your teens know about redtube).