But these are two different things though. In this case Streicher was taking action. He was directly working for the Nazi party, and his job was to convince people that the Nazi crimes were not only okay, but they should be celebrated and expanded. His actions actively aided the genocide, he was a part of the Nazi machine. That's not a private citizen with personal opinions and beliefs.
That's very a big difference between him and some modern neo nazi who spends all day picking his nose, scratching his ass, and posting on 8chan about the world is controlled by the "joos". As long dickheads like this keep their vile views to themselves, then I don't think they should be legally persecuted simply for holding vile opinions. However, the moment their words turn into actions or the clear intention to implement neo nazi bullshit, then that's when they should get persecuted by the law.