Why do EU citizens think that mass-surveillance is already applied by the US-gov on data stored in the EU?
Why would we not?
World over we have examples of governments sucking as much data as they can, on grounds of 'piracy', 'terrorism', and 'will nobody think of the children', and yet while all claim great strides are made in safety, extreme plots brought to the ground, and the like, somehow no-one (except an occasional token appearance) appears in court, and the piracy, terrorism, and child abuse goes on.
There is absolutely no evidence available to the average citizen that these processes work, or indeed what it is that they are supposed to achieve.
Once again: dear government, mind your own bloody business. When you have at least sufficient other evidence to believe I have committed an offence, then you may try and convince a judge that access to any data I may have left scattered around the place is to be made available to you. Requiring companies to store my data and metadata on the offchance that one day you may want to see it is neither efficient nor productive.
So I don't care whether you're my government, or you're an overseas government which is publicly demonstrating an appetite for grabbing all you can: no.