Rust is socially vaguely on the left/progressive side, yes. Not so much economically of course, because of all the corporate involvement.
GNU has some right-wing libertarian culture in it, but is also vaguely leftist and anti-corporate otherwise. I would actually say Rust is slightly more progressive than GNU on social issues, but not by much; and GNU is more anti-corporate, but also not by much.
I know there some other more certainly leftist FOSS projects out there (like the one we're chatting on right now 😉) but overall Nix is pretty good on that front.