I don't think its a horrible idea however the practice of it is the problem. If it wasn't going to be some SJW nonsense then yeah I think LGBT history is a part of American history. Nothing wrong with learning about it at a high school level. However I think we all know since an inch has been given they will take it a mile and turn something simple to some abusrd chapter about how they're all victims and yadda yadda yadda.
This is why we can't have nice things.