There are quite a few misconceptions and falsehoods in your post.
(1) The U.S. did not "supply" chemical weapons to Saddam. The people that say this point to some industrial and agricultural chemicals that could have been altered to produce a chemical agent, which can be said about every country on Earth.
(2) WMD. You have to put the WMD debate in the context of a post-9-11 foreign policy. The greatest fear of the intelligence community in the U.S. was that a rogue regime would supply a terrorist group with chemical, biological, or nuclear weapons. The international community had their intelligence agencies come up with the worst possible scenario, and each one, including Russia, France, Great Britain, and many more, felt that Saddam posed the greatest risk in this area. Saddam refused to cooperate in weapons inspections and the rest is history.
(3) Blaming the U.S. for the Oil for Food program is simply not based in reality. The problem with Oil for Food was Saddam himself, who instead of using these funds for his people's needs, built new palaces and increased military spending.
(4) Then we have the "600,000" Iraqi dead statistical estimate, which isn't about how many Iraqis were killed by Americans, it is about how many Iraqis have died from violent causes since the Iraq War began, ranging from criminal activity, Sunni and Shia death squads, stampedes at religious events, etc. Extremely misleading in this context.