“why are we speculating”
Because if the rumors were true, that would mean there were literally tons of unaccounted for wmd floating around a lawless civil war zone. That would be bad, and is worth considering as a possibility that we should try to address. And George Bush doesn’t know any more than what intelligence agencies tell him - the same ones that originally told him there were wmd. So his opinion is not a conclusive argument.
I remember before the war, Powell presented a lot of evidence of mobile (and sometimes dual use) facilities in Iraq. These facilities (which were shown in sat photos) have not all been found - so its not unreasonable to believe that they were moved somewhere.
Info before the war seems to have been crap.
PS: When I wrote “why are we speculating” it is to say that the issue was already settled after the fact and we now know what we didn’t. Seems all the Iraq informants were drunks and liars and told their handlers what they wanted to hear for money, etc.