Laos and Cambodia weren't participants in the war but that doesn't really feel like it matters all that much. Whenever I talk about the bombings of Cambodia and Laos with Americans (who - liberals and conservatives alike feel they must always defend) I sometimes here "well we bombed cities in Germany and Japan in WW2 and no one talks about those being war crimes". But were they? I really don't know much about those bombings. My gut says yes they were also war crimes but we just accept them because they were combatant countries?
yeah. it looks like it wasn't really challenged until after 2010, which was a little after I finished high school (and read Slaughterhouse Five as well, which I really liked).
There's also something to be said for the fact that 25,000 dead and 100k injured or whatever is still pretty damn bad. The tragedy and horror of Dresden is still more or less accurately captured by history, I think, even as we are now doing a better job of weeding out Nazi lies (as well we should!!)