The issue here is that some German economists under Professor Sinn have broken away from the mainstream, and the mainstream economists are livid. Whenever you show a groupthinker that he has adopted the fallacies of a group, you get a very violent, emotional reaction. Humans get very defensive about their beliefs, and the reaction is not surprising.
Groupthinking is not thinking. It is believing. Belief attaches itself to very powerful emotional centers in the brain, and belief does not go quietly into the night. The reactionary German economists are having their beliefs assailed, and they will defend them to the death of the German economy.