Do you use your computer to do anything secure like log in to your bank? How about you give me 1 week with your computer out of your control along with any BIOS/UEFI passwords, then after I return it to you would you still trust it to log in to your bank? Would you think you could sufficiently vet all the software and hardware to ensure I had done nothing to the computer?

Now instead assume I am only given 10 minutes with your computer, and not even the computer it self, just a touch screen with no access to any of the physical ports, and I'm only allowed to use a very limited guest account that can only run one program that is auto run and the account logs out if that program closes. Would you feel safe using that computer afterwards?

> Shouldn't these machines simply be able to get a new image written to them and be good to go?

If you lose trust in the hardware there is next to nothing you can do in software to rectify the problem. The quote "no methods exist to adequately secure them" might be going to far, but it's entirely reasonable to say it would be cheaper to buy 5 new machines than it would be to fully verify and recertify 1 of the spoiled machines.