Yes, it's hilarious at the hypocrisy. If Bush, McCain or Romney would have been President they, and many others, would be screaming to the skies about how this is illegal, etc.
I acknowledge that it's illegal under international law.
where within international law is it the job of the USA to unilaterally prosecute or punish war crimes?
Nowhere. Like I said I acknowledge that the United States bombing Syria is probably illegal under international law. (Though if you want to get into legal hypothetical trolling, considering that the US has recognized the opposition as the legitimate government of Syria, if they request our assistance in defending "their state" from Assad, that would be legal...)