It's not "I believe that fair taxation, transparent government and high standard public services" that is the extreme, abnormal opinion—it's "because you don't, you should be sent to death camp".

In a society where the norm is to value individual security, liberty and bodily inviolability, "violent reaction to opposing views" is necessarily preceded by an extreme opinion. Maybe that opinion only exists in a brief, heated moment, and it's certainly not limited to extremists, but extreme nonetheless.