The question can be interpreted in different ways.
When someone says, “Was the war about oil?”
I can answer in two ways.
If they obviously mean, “Hi, I’m a typical tin-foil conspiracy theorist SDer, do you think Bush started the war to raid the U.S. treasury by giving lucrative construction contracts to his buddies, and also of course enrich mulitnational oil corporations too, and then himself get massive “perks”, enriching himself?”
I reply, “Hi, you’re really a dumb person. I wish your life could have turned out better for you. Hey, look, I can make it better, here’s some weed, you like weed, right? Of course you do. Good boy!.”
If they mean it as a more legitimate question, I have a more appropriate answer.
Yes, oil had something to do with it. Wolfowitz (IIRC) said it best, the difference between Saddam Hussein and any other dictator is Saddam Hussein is sitting on all the wealth he would ever need to produce and create some very nasty stuff (global destabilization, large conventional army et cetra, even not talking about WMD). For ten years he had been mostly restrained from doing this overtly because of the post Gulf War I sanctions. However, in recent years, those sanctions were slowly being torn down. It was not inconceivable that within a decade or so, Saddam would be free from the world condemnation and then able to easily become vastly wealthier, which makes him a great threat to the world.
Kim for example, was not even as much of a threat, because aside from some nukes, he really doesn’t have anything. He doesn’t have any serious natural resources that could ever make North Korea a huge super power or anything like that.
Furthermore, the oil is important because it is a strategic resource, and it is important that resources that so effect the entire world not be controlled by a madman.
However, the oil aspect was only part of the whole pitcure, and not the overall point of the war. To say the war has nothing to do with oil is wrong, to say it is “all about oil” is also wrong.