[bumholio]

I stopped reading after:

All your suggestion does is, it adds a layer or two where we hope the NSA doesn't compromise them in case you'd want to use that chain to install and validate Signal.

You can't possibly think that compromising the full infrastructure of MIT or F-Droid, a noisy criminal act with serious repercussions against the perpetrators, is in any way comparable to a MITM against a suspect.

That's like saying "Ok, North Korea has some small nukes, but if they really want to get serious about a nuclear attack, they can always penetrate the White House and steal the nuclear football from under Trump's ass".