Nothing that transpires between a dude wearing a Trump shirt and a random person in an Indian restaurant is going to move the needle on fascism. Now we're just getting sensationalist.
I'm well aware of that fact. Like I said, I'm simply saying that the OP's angry response is understandable. I don't think he's a bad person for feeling how he did. Thinking about how punching the guy is going to affect fascism as an overall movement in the US is a logical argument. OP admits to having an emotional reaction in the moment. There's a difference between the two. No one is completely rational all the time.
And anyway, it's more that I find your overall attitude to be too easy on the idea of fascism. You tell yourself it could never happen here (or wherever you are) for comfort, I assume? For me, personally, and learning what I have about what fascism can lead to, any amount of it is downright scary to me. Again, I'm simply saying that I can understand the OP's anger. He isn't unreasonable or crazy for his response.