This is a question and i'm not trying to dunk on the tweet
I thought the main reason why those were bad because it mocked black people and they were the target of the ridicule, and while Cohen uses a similar technique in Borat he is targeting Americans as part of his satire, not Kazakhs.
I saw a criticism in vein of "People he can mock by making them think Kazakhs are actually like this would also believe that there is a country called Loftristan and its people act like that" and i can accept that, but comparison to blackface makes almost zero sense to me.
Most of the qanon people would believe loftristan, but maybe not someone like Giuliani or other gov officials.
I do not think it’s blackface and I’d argue that suggestion on its own is problematic. But his portrayal does betray a priority on who to communicate with and who to consider respectfully when creating the story.