Dude, they dropped 2 nuclear bombs. They treated them like trash. Everyone hated the Japanese much like they hated commies. Just the shallow evidence is overwhelming.

Here is a short link to remind you are "intentionally killing"

here is some more reading to add to your research:

https://www.darkmoon.me/2015/the-untold-story-of-american-war-crimes-in-japan-part-1/