If they are objectively spreading false information over and over again, then it is very much right.
To be case-specific: You have to be a complete nutjob to believe the flat-Earth bullshit; they are similar to the anti-vaxxers gang (although the latter causes much more collateral damage). On the other hand, you have to be a nutjob to willingly transact with a flat-Earth believer if you don't have to.