I am sure that Hitler would have approved of your elastic sense of morality.
How nice to know that American soldiers need fear no interference when they behave worse than maurauding Huns in countries that have never done the USA any harm.
I happen to think that invading Iraq WAS a war crime, and that many in the Bush Administration should have been tried in the ICC for that. I also think that everyone connected with torture should be right there in the docket with them.
But in the case of the military conflict between Al Queda and the US, everything the US has done is justified: Al Queda declared war on us, and their 9/11 attack on the World Trade Center was an illegal attack on a non-military target. (I think their attack on the Pentagon was NOT a war crime, since it is a proper military target. Their unsuccessful attack on the White House would also have been legitimate.)
So what are the Al Queda equivalents of the Pentagon? It is simply wherever their top leaders happens to be based, as they direct their troops. US drone attacks (or any other type of attacks) are not being directed at random groups of civilians. They are being made on locations where US intel leads us to believe (strongly) that Al Queda troops and/or leadership are present.
In summary: Intentional attacks on civilian populations are war crimes. Accidental civilian casualties in the course of attacks on military targets are not, but they should be minimized to the greatest extent possible simply because that is the right thing to do. There is no moral elasticity involved, just the rules of war in the real world.