It's perfectly possible to discuss the misogyny and sexism of drag without getting into the race/blackface issue..
Drag is a culture - the whole premise or 'joke' is that men 'abase' or ridicule themselves by dressing like women and taking on a hyper feminine appearance.
'He claimed women drag artists lack 'danger and irony' - in part because men dressing in women's clothes is an overt rejection of masculinity'
It's not 'ironic' for women to dress in a hyper-feminised manner is what he's saying here. Because he is unable to separate women from hyper-feminine. He's seeing those feminist stereotypes as intrinsically buried within women, the 'feminine' gender as being inherent and inborn to women. Saying that women and their gendered stereotypes are intrinsically linked in these ways is to say that hair, make up, tits, frocks, heels are part of the condition of 'woman'. It's also inferring that an extreme focus on appearance is somehow 'feminine'.
If he says there is no irony in women dressing as feminine he is saying women are feminine and can't escape that 'gender', can't comment on it, examine it from an objective point of view, can't be outside of that 'gender'. They should only live within it, never poke fun, never question it or mock it.
That's my reading of it, anyway.
Then again, he's calling it a rejection of masculinity. Is it? Wouldn't that entail men actually acting in ways that are considered not-masculine? That would be ... caring, kind, gentle, what am I missing. Drag queens are known for being outrageous, loud, funny, crass, ridiculous. It's showing a man taking on the outward stereotypes of femininity is ridiculous. To me it seems to be doing the opposite of rejecting masculinity. It's playing against the stereotype of masculinity, but it's not really undermining it, is it?