Can we not call it 'womanface'?
I understand why it gets called that, and goodness knows I don't like drag. But we should be able to articulate our problems with it without just pointing to blackface. It strikes me as parasiting off the work of black civil rights campaigners.
Did the people who campaigned against blackface have anything to use as some sort of cultural shorthand for why it was offensive, when they sought to change public attitudes? I can't think that they did. They had to explain why it was demeaning each and every time. We should be able to do the same.
Besides, if women simply say that drag is like blackface without further explanation, what's to stop the audience drawing the totally opposite conclusion from the one intended? People could decide that if drag and blackface are equivalent, then blackface should be acceptable again! I am sure no-one here wants that to happen.