Another great post. This has been a long standing pet peeve of mine.
My problem is that I don't have the energy or desire to debate with the flat earth folks.
Having flown
Toronto -> London --> Tokyo --> Toronto at altitudes where I can see the curvature of the earth, I'm quite positive that the earth is round.
I also work for a company that provides computer equipment that is installed in satellites.
When I tried to discuss this once, the first response was that the curvature I see is refraction from the window of the plane. From there, it just goes downhill.
Yes rigid and unmoveable thinking is bad no matter which side of an issue people are on.