People on youtube and reddit joke and make fun of sites like tumblr and tapas, and post "there's only two genders" comments all over the place.
People on tumblr and tapas make fun of redditors and the toxicity of youtube, and here a "only two genders" joke wouldn't fly most of the time.
It's simply a matter of likeminded people gathering and sharing stories about things they like and, yes, things they don't like.
This doesn't mean there is neccessity for change on these sites. Hate is the price you pay for being famous, that goes for companies too. You get even more hate if a certain type of political opinion is more common in relation to you than another.
Attempts to silence or change their own community to make bigots feel more welcome would only hurt their company and site users.
Tapas is progressive and a flourishing community of minorities that otherwise wouldn't have content they can relate to and enjoy and wouldn't meet the same, if any, amount of friends that truly understand them. If you look at something like that and call it "Snowflakes" or "SJW" then that's up to you and your problem to carry. The community remains strong and loving, and Tapas as a company continues to grow regardless so eh, have fun with your little issues. Your deal to deal with, dude.