Once you start gatekeeping who can attend a public event then it is not a public event and becomes exclusive.
And if you try to dictate what members of the public can and can't go to a public event, then you are liable to end up being a fascist...
My observation has been that for quite a few people like antelope, the line seems to be around immigration. If there is any claim by a person or group that current immigration policies are a problem and need to be more restrictive in some way, it's far-right, and possibly fascist.
I remember when the left used to have concerns about immigration being used as a tool by business and government to suppress wages.
The fact that they can't even think about this shows how much they're totally in thrall to "signalling". They have to be totally 100% in favour of more immigration, always, for exactly the same reason they have to be totally 100% in favour of bigger prosthetic boobs for male teachers, always. It's to signal that they're not like the "bad people", who only have issues because they're fascists/bigots/whatever.
They're no longer capable of actually looking at something objectively and judging it on its merits. It's all about who else does and doesn't support it, and how you indicate which group you belong to.
And then when no-one wants to support them any more, because they're clearly idiots incapable of making coherent arguments for what they do and don't support, they just denounce all those no longer supporting them as fascists/bigots/whatever.
And you know what - I do believe there are still real fascists out there. I just no longer have any idea who they are. Probably not anyone being called "fascist" though, as it's safer and more productive to call non-fascists fascists...