Flat Earthers and what to do with them

So you don't feel any sense of responsibility to guide them back from the edge of insanity?

That's a tough one. Of course if they are your friends, you'd like to 'help' them (but they probably won't see it that way). But in my opinion it's futile. In order to believe the earth is flat, you have to reject so many basic things, that I think it's a lost cause.