The school attack was a double tap. A triple tap, even: first one strike, then a second strike timed when first responders would be assumed to be at the scene, then a hit on the closest medical clinic.

Where's the legal trouble?

Hegseth specifically said they wouldn't bother with rules of war, they are confirmed to have committed one thing even you agree is a war crime, so why do you want to give them the benefit of the doubt on the choice of target?

I don't think you would have given declared US enemies the benefit of that doubt, in a similar situation.