Not sure about that. I for instance highly appreciate how security treated me in Japan, Thailand, and many of the countries in Africa I traveled to in the past months. Generally security in Skandinavia great, too. What I want to say is that there are many ways of screening passengers.

As a passenger I'm very keen on having good security on my flight. (I have been on flights where I didn't really feel safe). But in my experience the TSA is one of the most stressful, pushy and rude ways you can screen passengers and I think that the TSA's bad image has somthing to do with that.