It’s more that what’s taught in American schools varies wildly between states, as it’s generally left up to them to determine agendas individually. And schools and even individual teachers are going to choose for themselves how deeply things get covered.

For me, LGBT involvement was at least acknowledged when we covered the history of the Civil Rights movement. We were also shown a biographical film on the start of the AIDs epidemic when discussing viruses in biology. It made victims look very sympathetic, while the politicians that were uninterested in stopping the spread until it started affecting people outside of gay communities were rightfully depicted as villains. It probably came up in health classes too, but I don’t remember anything distinctly.