There's a discussion to be had around the burqua and how to ensure that women aren't be coerced into wearing it, much like we should discuss how some companies/establishments can demand that women wear heels and makeup.
Boris didn't do that though. He offered some lip service about the evils of oppression, then ridiculed in abusive terms the women that are, according to him, being oppressed.
If a woman is being forced into a burqua, how is mocking her appearance going to help her?
If a woman chooses the burqua, then you could argue that its just taking the piss out of her dress sense - but seriously, don't women have enough of that already without fucking BoJo slagging them off in a national newspaper?
Given BoJo's past racist and sexist comments, and that he's recently been chatting with a white supremacist, and now targeting the women of a minority that's suffering from increasing abuse - I can't see how he can stay in the party, especially after doubling down.