How about the police pulling up outside a neighborhood and making everyone get in a line for TSA-like gropes and clone everyone's cellphone because there were some crimes in the area recently (this actually happens now, not entire neighborhoods but select individuals at their whim).
Tell me where you draw the line and how police won't immediately abuse any power they are given? Let me know how you feel after your first encounter with the police someday.
And it looks like it's not just Germany: http://news.bbc.co.uk/2/hi/americas/4161983.stm
I think part of the problem is that the reasonings in these cases aren't out of this world. So people will think of the whole issue as much less problematic.
Of course you can always just hint that they are acting a bit naziest. Makes them shut up really fast (totally unfair tactic, but it works).
All they have to do is pretend to terry-stop you for any reason and demand ID then. No judge will ever sanction them.
Courts have been plenty willing to overturn arrests in such circumstances. Moreover, while the cops are largely able to get away with that kind of behavior, it is still illegal for them to do so.
Also, I wasn't able to find any evidence of cops being able to detain you in jail for hours on a Terry stop. Can you give a reference?