It seems to me that the author wants to have it both ways. IMO he is saying that the motivations behind the speech are the difference between the play and the neo-Nazis. If the litmus test to ban speech is "that which threatens Democracy", then you are going to have a lot of different interpretations of what does and doesn't threaten democracy. Also, if everyone wants to be a Nazi, isn't that democracy in action? As uncomfortable as some political or religious views might be, a democracy depends upon the freedom of expression of those views, even when they are made against Democracy itself. I actually see this author's view on free speech as hypocritcal.
Or if one person wants to be a Nazi, isn't that democracy. My Mom really helped me develop my personal viewpoint on free speech. When she made charitable donations she would tell me about who she donated to and why. We didn't have a lot of money for many years (divorce, single mom, teachers salary, could be much worse, but we knew the value of a dollar), but part of our household budget would go to support causes she believed in. One of the causes she constantly supported was the ACLU. She talked to me about how sometimes it bothered her that some of her donation would go toward things like fighting for the right of Nazis to march in public places, but that it was also important that all people have the right to voice their opinions no matter how offensive others might find it. Maybe I am just indoctrinated by my mother into believing that everyone should have the right to free speech no matter how offensive some might find their speech. I really think the only thing that effectively opposes offensive speech is more speech. Free speech protection is one of the areas that I think the U.S. is increasingly becoming an outlier in. Almost everyone, like the guy in this piece or some people here on Hubski, pretends to value it until they become offended at it. Seems like every month there is some kind of story about "offensive speech" being persecuted, prosecuted or banned in Europe. While generally I think of the E.U. as liberal and progressive, I'm glad that I live somewhere people are free to offend with relative impunity.