As a German I can say with certainty that only a very small number of people would get their panties in a twist about people saying they hate Germany. I'd want to know what the government had done, but the very idea that it was the same thing as "I hate you Germans." wouldn't cross my mind. Most German people can't be bothered with the amount of patriotism a US citizen seems to muster effortlessly.
Re: can of worms, twist key to open