I am not a tin-foil hat wearing person but I believe the Euros really didn't like the fact that the USA could deny access to the system with the push of a button, one of the reasons for Galileo.
I'm not sure if where you are born affects the conclusion that the system is prone to interference in the EMI sense, perhaps the political control one.
It's an impressive implementation of a simple idea, but if you rely on it as the sole means of navigation and you'll get what you deserve one day! I think the civilian gps is flawed in security terms due to lack of signing of the data, but i welcome corrections on that. I imagine truly malicious practical exploits would be difficult. I've just read there are some simple software based approaches to anti-spoofing - it would be interesting if these criteria are required for aviation.
It is a wonderful tool, and the greatest single improvement to safety in my 34 year flying career.
More so than ACAS/TCAS?