He is not coming to blackhat to talk about those issues. This deplatforming is just punishment for wrong think.

You could likely find something anti-science about most people. For instance a mind boggling number of people believe in ghosts, should they be disinvited? With regards to a security conference, it’s no more harmful of a world view than believing the Earth is flat. What about anti-vaxxers? Ban them too? Maybe come up with a list of beliefs you think are ideologically pure enough for the conference?

I don't believe either are the subject of the conference. And you've created a caricature to argue against, which is at best disingenuous. It's not possible to have reasoned debate in such an environment.

Not hearing him out will mean “They are trying to hide the truth. They are afraid he will convince more people that the flat earth is flat”

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.