I'm not sure that follows. First, funding != code. And the Underhanded C Contest exists because C kind of sucks; since Rust largely exists specifically to solve the problems with C, I would like rather more compelling evidence that underhanded Rust is possible than pointing at C.

The perceived adversary is not the NSA. Tor is mean to protect agents and journalists from average state level actors. It is not meant to protect you from superpowers that control most of the internets backbone. I would trust tor to protect me from Assad (or some other dictator of a mid level power) I would not trust it to keep me safe from Putin or Xi.