He got precisely the 'due process' that he himself meted out.
What's sauce for the goose is sauce for the gander.
Most of us have no experience of living under, and have never had to take up arms to defeat, a tyrant like Gadaffi, and are in no position to criticise the behaviour of those who have, and who have risked death for their freedom.

Had he lived, and if by some strange quirk of fate he managed to return to power (which is very much what the rebels would have feared), he would have murdered thousands in revenge. He got the same justice he was wont to hand out.

As the Americans say, "Good Jo-o-o-b".