It is definitely a case of mass histeria for the following reasons:

1) Germans have been taught to be ashamed of their past for what happened during WW2. (Note that the same shame isn't leveled against communists. Also not that the Anglo/French sphere are just as guilty for instigating WW1 & WW2)

Given this shame Germans feel they have to atone for their sins and many times literally self-flagellate.

2) In the post GW Bush and Iraq war era European socialists received tremendous validation as being an 'alternative to the Americans'. Even though their 'systems' (I hate thinking in this way) are actually quite similar with most differences being found in single payer healthcare and free speech.

Socialists and communists the world over kept using German and Scandinavian countries as examples to justify their misguided statism (Venezuela).

Now that this image is being succesfully challenged and intellectual leftists don't have an immediate moral highground for being an anti-american collectivist this results in massive histeria as instinctually people know that their ideologies and public appearance is going from worshipful to actual pitty or even disdain. Never underestimate the power of cognitive dissonance to produce violence.