He literally tweeted that any person who sided with Depp was a misogynist.The situation was a whole lot more complicated than that, for sure. But there were definitely a lot of people who sided with Depp because they were fans of his. Not to mention the fact that a huge swath of the MRA movement threw their weight behind him. The whole situation is really icky, and I don't think Grubb should have stepped in it here, but I don't think he has anything to apologize for.
I think it is just as weird, if not more weird, that a bunch of people are throwing a fit about Grubb's tweet here.