This might not be your style, but just telling the dude straight up that this is mainly a bitcoin space. No followup, no bullshit, no belittling, just a couple words straight to his ego. I know you advertise as a “crypto” meetup but it doesn’t hurt to throw something like that out there to mark your territory. See what happens. I too am opposed to conflict, but friction is a part of life. Sometimes by creating awkwardness you become the dominant figure once again by simply stating a fact. Fuck em. Who cares what his intentions are. Your space, your rules.
Just an idea. Might help you formulate your own tactics.