This is just so utterly over the top I'm mystified that it was taken as anything but ritual insulting for the purpose of bonding/hazing in an informal group.

You've been lucky to avoid seeing jokes like this more often when moving around the Internet, then. Over the top jokes at the expense of minority groups are popular when representing actual opinions, not just as jokes to people you already know, particularly in communities where those opinions are accepted norms and the group in question is an acceptable target. The desire to score points often leads to gross caricatures of such acceptable targets being thrown around. It's repugnant, but not that unusual. I've seen plenty of worse things said about gay people when trawling things.

To anyone who knows that these opinions aren't actually accepted norms, from time spent in #lesswrong, they're obvious jokes. But for a fairly new arrival, in the absence of this knowledge, and possibly with more experience of genuinely unpleasant communities, it's not an unreasonable interpretation.