I hear where you're coming from. It's a loaded topic, to be sure. I think it really comes down to what he's saying by dressing as Kanye. Are these two lampooning Kanye and Kim because they are celebrities or is it something that has a racial edge to it? Without seeing them in action, I can't say. And I admit that it's a judgement call in any case. As a white man it may be a different standard than for someone from a different background.
I think if someone black painted themselves white and dressed up as Donald Trump to make fun of Donald Trump, that's fine. If they did the same to make fun of white people, that's not fine. That's how I see this with Kanye. It's entirely dependent on the context. There should be room for satire and role playing, but we do need to be careful to not be falling into racism or stereotypes.