The only real way I see, is to straight up be emotionless in all interactions with them. Even the slightest bit of passion in it, even the tiniest bit of contempt, and they will adopt the armor of "They hate you, so you need to hate them more!"
The action has to be about the message and the actions, not the people. That's why it has to be emotionless, and resolute.
"I don't see how you can expect that from people" not withstanding, that is what is called for, and what is necessary.
You have to demonstrate, through words AND actions, that you are not after them personally (as people). The position is that their rhetoric and activities cannot be tolerated, and must be stopped. That divide between beliefs and personhood has to be reinforced. If you cross that line, even a little, it will be to all our detriment.
Ruining people's lives because they happened to be photographed on the scene of a fascist media event, because "guilt by association!!", is not how you do that. Spitting on people is not how you do that. Punching people is not how you do that.
Deplatforming, Encouraging service providers to follow the laws about hate speech, Assisting law enforcement and service providers to uphold those laws and requirements, while keeping a calm but stern face in public, and urging the media to stop covering these media events in any capacity besides raw informative reporting, talking with vulnerable friends and family to vaccinate them against the propaganda, and similar calculated but calm methods are how you deal with it at this stage.
Punching nazis is what comes when this stage fails. We are not there yet. Do not encourage that behavior, even though it might make you feel good.