People who are saying, "this backlash has been since Obama" are ignoring that the backlash until very recently was focused on the political, not the educational. Disrupting schoolboard meetings, banning BLM signs in schools, huge public drives to ban books, the CRT witch hunt, this is all very much a recent phenomena. Not that things like that never happened in isolation, but they weren't a driving cultural narrative until just now.
Schools rewriting history to be more pro-"white people" goes back over 100 years.
In the 1990s there was a big backlash against it and a lot of shyt started changing. Books like
Lies My Teacher Told Me - Wikipedia were required reading in many grad schools for aspiring teachers and administrators. This is also in line with the steady trend of teachers being more and more of a "liberal" profession, even in red states, so a lot of white conservative kids were finding their teacher to be the most liberal authority figure they encountered on a given day. The curriculum changed
significantly during this period.
Obviously since Obama there's been a big white conservative backlash built around racial resentment. But I believe it's only recently that they realized how much they were losing their own kids. Resentful white conservatives across the country saw their own children posting anti-white supremacy shyt on social media and holding up signs at BLM marches and flipped the fukk out.
I hadn't connected it myself, but can see a very real basis to the idea that the schools-focused manifestation of racial resentment is highly tied to young people's participation in the 2020 protests.