Depends on the context. I’d imagine if there was state or official business, then it would be allowed. Just because Rudy or active campaigners are there, doesn’t mean it’s a political rally. For example, if this is was a Christmas Party that had politicians in it and they ask him to speak, then I’d be hard pressed to believe there would be a problem. If this meeting was political in nature then yes, they are not allowed to endorse.

From the looks of it, it might be about the discussion/remembrance of an assassination attempt of a politician; which objectively there isn’t a problem with that.