But it still wasn't morally wrong.
We had at least 2 out of three, and arguably 3 out of 3 to make it right,(refering to Aquinas here).
He was harming his own people, he wasn't a good guy to have around, etc.. there were plenty of other reasons as well. The only reason to go after someone else isn't cause they do something he doesn't, but cause they do it on a larger scale, more publicly, etc. But to start a war against abusive rulers(morally right, yes?) why not get a good start? Such as Iraq. It fits all the neccesary components to be a good target in such a war(both morally and tactically).