This is a weird parallel to similar controversies in fiction.
So presumably an AI image generator generating images of historical figures in situations they never experienced, wearing clothes they never wore, in places they never visited, at times they didn't live through, using tools they never heard of, meeting people who's lives didn't overlap, saying things they never said in languages they never spoke etc. is fine but skin colour is a bridge too far because "historical realism" is soooooo important when using an AI image generator.