There is no choice but to civilly discuss ideas when the people advancing those ideas are likewise remaining civil. It is never acceptable to respond to peaceful, civil expression with violence. If you suggest that "fascists" who are expressing their ideas by say, writing an article, or standing on a soapbox in the middle of the town square are fair game for punching, then so to are communists, anarchists, and black bloc members are fair game. All one has to do is decide that the ideas being propagated are dangerous and a threat to well-being, and it provides as much justification as beating up fascists.
Nobody says you have to discuss anything with them. You can ignore them. You can yell and scream, and you can protest. Do what you want. But, no, you can't initiate violence against them.
A book named Mein Kampf is not in any way a reason to initiate force against Hitler and anyone who supports him. I read Mein Kampf in the local lending library. Should I have destroyed the book? Should I have punched the manager of the library?
This notion of yours is absurd, and no thinking person after the Enlightenment can hold it. You hate fascists, well so what? Fuck you. They hate you too, probably. And, maybe they think you're the dangerous one. So what is it now? A free for all? You want everyone to be allowed to beat up the supporters of ideas they think are hateful and evil? Or, are you suggesting that there is some objective mechanism to determine which ideas are actually going to be the ones that can get beaten up? The State is going to decide this? That would be absurd, wouldn't it -- since the State is usually the entity that does the oppressing and censoring, right?
When I hear this argument, it reminds of when I was a kid, and people would get asked the question "do you believe in free speech?" And, most everyone would say yes, but when the question was followed by "should a communist have free speech to spread their ideas?" A large percentage of people would say "no." To me, communism is an awful, hateful, terrible idea, and it is an insult to human dignity. Yet, I would never conclude that it should be appropriate to beat up communists for that reason. But, based on your logic, shouldn't it be o.k. to kick communists in the nuts and beat them down? After all, they're a danger to society.
And, who are you to say that "trump and his aides are not yet in the position where that can be said of them?" There is no arbiter, other than each individual, to say who is and is not a white supremacist -- I've heard it said of Trump and Bannon. Aren't they white supremacists? If I think they are, should I punch them in the face? Or, is there a vote we're going to take, or a legislative session, or a "Bureau of People We can Punch in the Face" which is going to determine which alleged Nazis and fascists and white supremacists are fair game?

“When I was in college, I took a terrorism class. ... The thing that was interesting in the class was every time the professor said ‘Al Qaeda’ his shoulders went up, But you know, it is that you don’t say ‘America’ with an intensity, you don’t say ‘England’ with the intensity. You don’t say ‘the army’ with the intensity,” she continued. “... But you say these names [Al Qaeda] because you want that word to carry weight. You want it to be something.” - Ilhan Omar