You come call me when the police stop doing their job and arresting people that are assaulting others. Police in this case were ready and willing to start the investigation and Adolf jr. didn't want to so...
And again^99 free speech is an issue between you and the government. It does not protect you from the consequences in public/private society. No one has to give you a right to spew hate filled rhetoric and while you do have a right not to get punched (assault, not freedom of speech) it's going to happen from time to time.
Speaking as someone on the left, I am disgusted by this. I hate neo-nazis, I think they're competitive for some of the worst people on the entire planet, and I think that their continued existence is a testament to how shitty Western civilization can still be at times. So the fact that some wannabe vigilante asshole has put me into a situation where I'm forced to defend a nazi bothers me to no end. Because there are tons of appropriate responses to a nazi passing out fliers, and 'putting on a mask and punching him in the face before running away' is NOT one of them.
And for anyone saying violence is okay because nazi have a history of violence themselves, there's a significant gulf between a clear and present threat and a theoretical one. Bluntly, it's not illegal to want someone to die (most of us, at one point or another when we were very angry, have secretly wished someone else would just die). It IS illegal to draft up a plan to murder someone. The 'here is how I plan on doing it' is kinda a critical threshold where it transitions from thought crime to actual crime. If there is any evidence that the guy passing out fliers has ever done, or seriously planned, violence he should be arrested and thrown in jail. But that still doesn't make a vigilante punch acceptable. Punching him doesn't make anybody safer, if anything, it puts people in greater danger because it gives him and his ilk something to point at to justify any violence they want to do in the future.