It's not geopolitics to try and determine if fewer people would die with or without Saddam in power. Saddam's chemical attacks against civilians are well documented and not widely disputed. His internal security apparatus was open with their brutality in order to induce fear on the population.
I think that the 2nd Iraq War was a mistake, particularly how the government misled the people, but I find it absolutely baffling when people will not even honestly address the situation in good faith. You cannot simply argue that "many people civilians died as a result of the Iraq War therefore it's bad" without addressing the situation beforehand. Lots of people died during the Allied invasion of Germany, but I think most people would agree that it was the correct thing to do.
The justification for the war was obviously fabricated, so I don't know what sort of good faith you are asking for. Perhaps to debate some post hoc justification for a thoughtless decision that was paid for with the lives of people who didn't have a choice in the matter? People who touch such questions are only going to injure their humanity.
By the way, when you think about the question of WW2 in terms of "when to intervene" instead of "whether to intervene at all", it becomes as murky and vicious a question as can be, and it ought to make anyone queasy to examine in close detail the decisions made throughout the period. That said, the neoconservative methodology of deciding who to bomb has no justification and people who want to debate that have more urgent issues to address.
I absolutely agree that talking about intervention is murky, which was precisely my point.