Obvious as it may sound, people with authoritarian beliefs hiding behind free speech actually consider it as a weakness akin empathy. It allows losers like them to amplify their reach despite not being in power. They abandon their “free speech absolutist” postures the moment they think they are in power.
It’s not legal, and I don’t know which judges are more lenient about this kind of thing. But if one can do it without being caught or attacked, like the two people who punched Richard Spenser, then it is an effective way to counter the rise of Nazism. Legality only matters if it’s enforceable.
All this does is bolster fascism. Punching people for being non-violent fuels their world views, not help them trust yours. Maybe engage in some peaceful discourse. You’re actually the one instigating violence here. You have the same attitude of cops shooting unarmed people.