The signs featured a man lying on the beach with a sombrero over his head and another covering the bits that need to be covered. There was that, the fact that it's a Cinco de Mayo party at all, and the unicorn pinata, and that's really all there was to the party. To the best of my knowledge he hasn't had a fight with anyone in the house or anything like that-- he's just like that; this isn't the only minority group he's "stood up for".
It just seems to me that in all of his speaking out, he only ends up upsetting people and calling controversy to the issue, and then claiming that the people who are upset are just racist/sexist/whatever-the-issue-of-the-moment is and don't want to check their privilege, and there really *has* to be a more appropriate way to go about raising issues like this that won't result in crazy amounts of drama.
I'm not actually sure whether it was unicorn or pinata that was the issue, although the phrasing used was always "*curse words* unicorn pinata" and followed by how racist it is; the two words were never used separately.