Most of the people killed by Saddam were killed during the time when the US was financing Saddam's murderous activities, and Saddam was doing his killing at the behest of and as proxy for the US. During the later years, the numbers of people being killed by Saddam had been reduced to a much smaller number. So using the excuse that getting rid of Saddam would reduce the numbers of people killed by him just doesn't stand up to scrutiny. More likely, the number of innocent civilians being killed by violence in Iraq has increased since the US led invasion as compared to the last few years of Saddam's rule.

During the last years of Saddam's rule, most of the people who died, did so as a result of the sanctions, not because of a lack of money (which Saddam diverted, as pdq has described) but because the way the sanctions were set up... even when the money was available, it was almost impossible to get certain life saving items into Iraq.