Trump threatening to end a civilization isn't a new novel thing. US presidents have commited genocides and atrocities throughout our history, we're just not taught it (or taught the myth version, which to be clear - are lies).
We're built on atrocities and genocide. The reason people are clutching their pearls over trump threatening Iran is because he shoved their faces in it.
It's fine if it's over there, unspoken in polite company. Ignoring (white/rich) crimes is as American as apple pie.