Dönitz's blanket order that no submarine should ever pick up survivors is absolutely not equivilant to any individidual submarine deciding not to pick up survivors because {reasons}.

The first is a blanket order to ignore all survivors all the time,

the second is a specific case of not picking up survivors under a general umbrella of picking up survivors save for when there are other factors.

In this specific instance they can argue, should it ever go before an international tribunal, that they lacked room and that more applicable search and rescue was already en route.

I'm not arguing in defence of Hegseth et al. but I am pointing out that things are not nearly as clear cut and straighforward as you claim.