That's irrelevent. And inaccurate. All you can say is they began fighting us there after we ousted Hussein. You have no way to validate the statement that they didn't operate in Iraq under Hussein.
Nor can you validate that they wouldn't have hidden in Iraq (or any other sympathetic country) if we had poured all our efforts into eradicating them in Afganistan. No more than I can say they would have. It's all "what if" supposition.