While I don't condone the actions of US Marines in urinating on a dead Taliban, the problem is that if the US apologises or takes drastic action against the Marines concerned it will be seen within the Islsmic world as yet another sign of American weakness.
That's what liberals fail to comprehend about Islam - that any willingness to negotiate or compromise or conciliate is interpreted as weakness.
And as Vietnam proved decisively, you're defeated when you believe yourself to be defeated. The US was winning that war militarily but that meant nothing once the news media convinced a significant portion of the American people that they were actually losing. Walter Cronkite turned out to be a more dangerous enemy than Ho Chi Minh.