Maybe, but there was some agreement and one party is not respecting it, so let's say is not nice not to respect your contracts. Star Trek fans are probably reminded by this rule of acquisitions; "A contract is a contract is a contract… but only between Ferengi."
The EU is not some weird hive-mind, it has separation of powers just like the US. It is the European Court of Justice's job to overturn executive decisions that trample on the constitutional rights of its citizens, same as the Supreme Court in the US.
I am not sure how your comment related to mine, maybe I was not clar, EU and US had a contract, US is not respecting it and this judges looked at teh facts and said, yeah the contract is invalid so you can't store private data in US using this contract as a base, find something else.
And now US citizens from HN spin this as protectionism or over regulation and just ignore that there was a such a contract and it was not respected, it would make sense then that US guys won't complain if someone else would do the same, but you notice if an app related to China is only suspected of doing something like that the mob demands it getting banned if an US entity has the power to just search and read anyone's private stuff that is not from US then is fine.
I mean US could pretend they won't spy , and then work a bit harder to get the data they need instead of having 100% full access to everything.