> So if it came out that the NSA was attempting to put backdoors in consumer password managers, it wouldn't change the context of the side channel attack?

Not really, we already know that NSA attempts shit like this all the time, if that came out, it'd be the same as the Snowden leaks meaning, a bunch of nerds going "Huh, who could have predicted this?". I don't see the point in it being Russia, China or the US, I'd like it as much if the US did it as Russia, so that's why I asked why it matters.