Yeah, it does seem excessive. Although the old cold war paradigm does see them in service in the arctic a lot, and whilst most of the ocean up there is ~-1.8'C you can get localized sections of water flow that are much cooler because of surface freezing concentrating salt levels and forming a column of water that can cool much further without freezing. Although I'd guess that kind of process would reach -10'C at most in natural conditions, and the absolute max you could do just by increasing salinity is -21'C. So still excessive.

Nonetheless, you don't do this passive aggressive "I think I know better, but won't actually confront anyone about it" bullshit, and you sure as shit don't falsify the specs. As you say they could repurpose it for something that does need those specs, because they were specifically told it meets them, and then someone ends up very dead.

[Edit] Fuck, never mind. The US has plenty of nuclear subs, there's nothing to say they wouldn't be in contact with some emergency cryogenic cooling system, or they don't keep liquid O2 onboard for extended underwater operations. Those cold specs could very much have been necessary.