I feel like the second paragraph wasn't there when I first replied to this, but if it was I just didn't notice it. I'd like to address it specifically either way.

I'm not at all saying "you can't compare anything to blackface." There are absolutely modern power structures that resemble it, and it is absolutely right to point them out and deal with them. I would never ever say that you shouldn't.

What I'm saying is that this is not a matter of scope but structure. Structurally, whatever you're seeing in Big Bang Theory does not resemble in any way what exists in traditional minstrelry. The people who are the butt of the joke in Big Bang Theory do not suffer systemic disadvantages in the way that Black people in the Jim Crowe era did, and they actually enjoy quite a lot of systemic advantages.

If merely caricaturing people for an audience to laugh at is sufficient justification for a comparison to minstrelry, then the entire comedy industry is and has always been guilty of it. As for unpopular, I'd also argue that there's a vast difference between unpopular and being treated as subhuman by law, to the point that they are not even close to the same thing. Black people being 'unpopular' is not why minstrelry was wrong.