The intelligence community would strongly disagree with that statement.
There is a logical path to follow that they did, indeed, have chemical weapons in Iraq and, a reasonable reason that finding any wasn't reported.
Step 1: There is, without a doubt in anyone's mind that Sadaam had them at one time since he used them on the Kurds. No question about this.
Step 2: The agreement with the world is that Sadaam would destroy said weapons AND provide proof along with allowing inspections. Inspections were thwarted consistently and obviously dog and pony shows.
Step 3: Sadaam, himself, said he had them. Maybe it was just showmanship, but silly showmanship when he was being faced with destruction. In any event, the agreement he reached to stay in power was that he would get rid of the chemical weapons and provide proof. He didn't provide proof and said he had them.
Step 4: What the invasion also didn't find was any proof that the weapons everyone knows he had were destroyed.
So, there are three likely outcomes:
1. He did destroy them but didn't keep proof. Clearly, unlikely.
2. He moved them before the invasion. Possible. Not sure how likely. There are some pretty good reasons to speculate where (Syria) that they went.
3. He never destroyed them and still had them when we invaded. Maybe, a little more likely than #2.
Either 2 or 3 (or a combination thereof), by logic almost has to be true. But why would we never report having found them, you ask? Because they were sold to him by us, which is why we were so certain he still had some. We knew how much we sold him and we knew about how much he used. It is way better to fend off the "see you didn't find WMD" BS than the "WTF are you doing broadcasting that we sold those to him" fiasco.
