There needs to be a middle ground between shutting down actual dialog and allowing flatearthers to suck all the air from the room. We all have limited time on this (roundish, mind you) earth and it sucks to have to rehash arguments. “No, no, just hear me out” is a hard thing to stomach from someone you know is yammering just to waste your time.

I think the worst thing you could do is invite a flat earther(or anyone else you disagree with) and then disinvite them. You have now given them a larger audience and new reason to say they are being censored.

Blacklists are the middle ground? There's probably a compromise somewhere, but this isn't a play for middle ground.

Incidentally, this is exactly what they’ll say if you do hear him out.