It was clearly a tragedy. Very few Americans--certainly I've never met one--support that strike in retrospect. Instead they are angry that such a terrible mistake was possible and they generally want a thorough investigation and targeting procedure reforms to make sure it doesn't happen again.
Americans hold their military to a high moral standard. But wars don't have to be fought so cleanly. Certainly the Golden Horde had no compunction about genocide. If acknowledging our shared humanity with innocent victims and expressing remorse for their deaths is ridiculed, then we're primed for a descent into nihilism, wanton cruelty, and mass slaughter.
EDIT: @Hikikomori, I cannot reply to your post, but I am happy to engage if you follow HN guidelines: https://news.ycombinator.com/newsguidelines.html
> When disagreeing, please reply to the argument
> Please don't post shallow dismissals
But nothing anywhere in any of these increasingly pathological threads do I see evidence of a war crime. Tragedy yes, intentional crime, no. Preventable yes, cold blooded intentional child murder no.