"couldn't it be argued that the use of body-scanners functions as a form of strong deterrent for potential plots?"

Not when all the materials one needs to construct a dangerous weapon are available on the other side of the checkpoint. Go to the duty-free shop and buy a glass bottle, and now you are ready to make a shiv.

For that matter, you have lots of sharp metal things and dangerous chemicals in your laptop, and you can walk through security with that.

I doubt the 9/11 hijackers would be deterred by the nude scanners. Sure, you would stop them from bringing a box cutter through (maybe), but there are a dozen other weapons they could have carried through or procured past the checkpoint. The nude scanners might catch someone who is trying to sneak a gun through security, but so do metal detectors -- and metal detectors might even do a better job.