I found the video. Challans was absolutely rude, boorish, confrontational, and a jerk. Not a neighbor I'd want.
Mielke was calm, polite, level-headed and defused the situation by separating himself from it. He did flub an opportunity as quoted in the posted article.
Mielke, 36, who is gay, acknowledged Challans’ apology and said the fine was reasonable
“It seems the issue is resolved and that is fantastic,” he said.
Would have been so much better if he'd said "fabulous" instead of "fantastic."
All that said, Challans did not appear to do anything that crossed out of the realm of Constitutionally protected speech. If he had the money to burn or a friendly attorney I bet he could have easily had that conviction overturned, but it would have cost a whole lot more than $200. Unlike back when groups like the ACLU would defend nasty people because they respected a principle that more free speech was good even if it was ugly, today that view has been largely displaced by the view that "if it hurts the feelings of just one person (that I deem worthy of protection), then it should be illegal!" That sort of limits the opportunities for pro-bono defense against bad laws like this.
I'm pretty sure that despite his sarcastic send up of kgb's understanding of Constitutional law and the fact that his much greater training in the subject ought to give him the tools to know better, MillCreek's position on hate speech is in outright contradiction not merely with the Constitution, but Supreme Court rulings as well - including the very cases referenced in the link he posted. I can find absolutely no legal definition of hate speech in US law, and as I mentioned before "fighting words" would be the only possible exception that could apply here which would be quite a stretch and certainly not an interpretation evenly applied.
My impression is that MillCreek's perspective on this is influenced more by emotion than by either legal understanding or principle. It was amusing that when giving examples of what he would consider hate speech he explicitly dismisses an anti-white epithet as not hate speech.