Pro tip : just because some claims to be rational doesn't mean that they actually are

This is an old one, but glorious :

I understand that most people see the Flat Earth Society's views as extremely unorthodox and perhaps a bit kooky. I'd like the public to know, though, that our views are based on extensive research and we highly value the pursuit of truth. In fact, the Society's motto is (and has been since the 1800's) "In Veritate Victoria" -- Victory in Truth.

Which is also why when people declare themselves not to be racist, I generally stop taking them seriously. Of course, it's also possible that Flat Earthers do care about the truth but are just extremely stupid. Probably a large dose of rampant denialism and stupidity, I reckon.
https://www.businessinsider.com/flat-earth-society-to-obama-climate-change-speech-georgetown-2013-6?IR=T