Q. Is this really as harmful as you think?
A. Go to your parents house, your grandparents house etc and look at their Windows PC, look at the installed software in the past year, and try to use the device. Run some antivirus scans. There’s no way this implementation doesn’t end in tears — there’s a reason there’s a trillion dollar security industry, and that most problems revolve around malware and endpoints.
Not that it solves the problem, but since I’m not the King of M$ this is about all I can do: you could easily get around all that by turning off secure boot and booting into a persistant live-usb containing a linux distro of your choice (Tails for extra privacy/ease, if you can use Tor) to do all your secret agent computing needs. The host PC can’t see shit of what happens on Tails.