One of the most insulting things you could do to a German audience is given them a nazi salute. The WWE members shoudld've been given a few pointers before entering the country. Simply being "the bad guy" isn't an excuse for abuse like that; portraying a redneck for the public's amusement was about as far as it should've gone, and even that is arguable. Naziism is Germany's, and perhaps the world's, most terrible memory of the past, the ultimate symbol of how low humanity can go. For anyone to publicly invoke those images just to get a response during an entertainment event really isn't on, in my opinion.
The WCW's short-lived "West Texas Rednecks" managed to be provacative and sometimes amusing, without being degrading or insulting. Pro-wrestling is dependent on overblown, outlandish personae, but things should not get taken too far. Nazi-saluting a German audience is clearly too far.