After all, the expulsions are happening for a reason. The Spanish clearly do not see it as you do.
It might be possible for the US to avoid many consequences of this kind of thing due to its clout, and I can see that as something which would make it feel normal from a US point of view, but from the other side I imagine that it feels like someone trying to infiltrate your government to do things against your interests and to harm you-- something warranting a very high level of concern, comparable to a planned coup.
It's so normal that the term "diplomatic cover" exists to describe non-clandestine spies who are given a position in their country's embassy.
But the fact that the country is a formal ally makes it, in my view at least, slightly different.
Of course, seeing as the US is in a defence pact with Turkey, I can understand that being ally can't mean absolute non-interference, but I feel that it gets problematic when we're talking about actual infiltration of a country's security services.
I think at least the Germans expected some restraint. I suppose if one thinks back, the Germans had a different view, being opposed to giving Turkey bad crypto; and I suppose that can be seen as them restraining their activities in an unreasonable way, at the same time, I can't accept that bribing/blackmail people on the other side is compatible with an alliance. Rather, with enough bribes/blackmail the result is a secret coup of the state whose personnel is being bribed or blackmailed, and I think if you view these things as 'normal' then you might even be blind to such a coup against yourself.
You don't publicly expel them unless you really want to weaken the alliance, and you certainly don't torture them like some of the commenters in this thread are suggesting. They watch too many movies.
LOL. I bet the US never does this.
Those countries are already not souverane anymore. Notice how the external, and even internal politics of those countries are dictated by the US ?
It seems like a self-defeating exercise.
If the 'allies' are only faithful and only believe each other until the moment that threshold is crossed then it's just regular diplomatic relations.
e.g. Nearly every country cooperates with nearly every other country on such terms in the areas where they share bonafide mutual interests.