War was not the only option to respond to the crime.

FWIW I'd agree your question wasn't what-about-ism.

You don't have to forget anything, just contextualize it. The United States already tried installing a puppet government in Iran and it went terribly. They were so unpopular that the CIA set up state-sponsored torture rings to quell dissent: https://en.wikipedia.org/wiki/SAVAK

Going back to the old way foments instability that jeopardizes the Gulf States, with precisely zero upsides to anyone that isn't a net oil exporter (namely, the US and Russia). If this was about protecting against genocide then the US would be invading Sudan and Gaza, not Iran. The death toll has nothing to do with how American leadership sees this conflict, and it has been like that for over half of a century.