At that time plenty of western countries were ready and willing to build chemical and nuclear plants that had dual use capabilities and even after it was pretty apparent they were being used for weapons neither the companies nor countries really cared unless they were a committed enemy. Thus German, French, and U.S. companies all contributed to Saddam chemical and biological weapons and nuclear programs. The Reagan administration provided targeting for the Iraqi forces during the Iran-Iraq War and knew about the chemical weapons and actually released some statements blaming Iran for the attacks. When Saddam attacked the Kurds in Halabja, Washington again denied that anything bad had happened and even stymied an investigation if my memory serves me right. Halabja was actually part of the Iran-Iraq War having been captured by Iranian and Kurdish forces before the chemical attack.

Iran after the 1979 Revolution was the new bogeyman and the U.S. was perfectly happy to see Saddam use any means he had at his disposal to fight Khomeini.

That Foreign Policy article just came out at the end of last year, but it was all common knowledge even when it happened in the 1980s and was reported in the mainstream press, and again during the Gulf War, and for a third time during the first round of inspections. It's just that either people forgot about it, or Iraq was not a main topic of their studies.