I'm not making a hypothesis.
I am showing that positive identification is impossible via a process of elimination considering the sources of DNA,ie, a hotel room, rental car, and manhaten (sp??). Those are highly contaminated areas.
You are making a hypothesis to justify your claim that positive identification is impossible. However, your hypothesis is that positive identification is impossible if there are additional DNA traces that cannot be eliminated. I'd like to propose a counter-hypothesis (actually I already have, but you haven't satisfactorily addressed it).
Suppose only ten DNA traces were found in hotel rooms and hire cars that could not be identified and eliminated, and ten names were found on hotel registers and car hire documentation. Can we therefore assign,
with a reasonable degree of confidence, those ten DNA traces to those ten individuals? In order for a false positive to be recorded, we require two things to have happened:
(1) Some other individual has left DNA traces in both hotel room and hire car. You've come up with a possible explanation of that.
(2) The individual we believe we have identified has left no DNA traces in either the hotel room or the hire car. You have
not come up with even a vaguely plausible explanation here. How can one of our suspects drive a hire car and occupy a hotel room without shedding any skin or hair? Gloves while driving might explain lack of skin flakes on the driving wheel, but what about debris and detritus elsewhere in the car?
Remember, we have plenty of time for a very thorough analysis of the scene; the DNA profiles weren't produced until over a year after the attacks. Until you can explain how one or more of the hijackers could have left no DNA traces whatsoever in their hotel room or hire car, then you haven't established your claim.
Dave