The US had no qualms making itself a pariah amongst its UN allies by spying on them back in 2010, germany included, when biden was still vice president no less, so I don't think that's much of an argument against them doing it. Especially when you are talking about NATO, an organization where the US power imbalance is even higher.
That isn't enough to blame them for it of course, but to assume that Putin is not behaving logically because the alternatives are so "unthinkable" is misguided.
News for you: Everyone is spying on everyone else. Always have, always will be. Germany was also spying on the US. Spying, a.k.a having inside knowledge, is always a preference by all regimes. Whether one has the means to do it is another matter.
That isn't enough to blame them for it of course, but to assume that Putin is not behaving logically because the alternatives are so "unthinkable" is misguided.