What states are banning teaching black history?

There are certainly states banning things, and what they are banning may be problematic, but I think you've captured neither the intent nor the impact of any law or proposed law that I'm familiar with. I don't spend very much effort scrutinizing bad laws in places I don't live in, so it's possible that one or two slipped past me--feel free to link the text of the bill and/or discussions thereof and enlighten me! But I suspect that you're repeating statements made to rally voters that assumes those states will fall all the way down a slope that isn't even even known to be slippery.