I call groups like this "conspiracy theorists." We have the science, we can test the data, we've spent generations now studying this. But despite this, there are groups that deny the science. And why? To Creationists, the science is a trap from the pit of hell. To flat-earthers, the science is an attempt at holding us back... Behind every one of these groups are conspiracy theories, which is why they refuse to "believe" anything other than their own ideologies.

I'm actually using the flat-Earthers as a springboard into a critical thinking unit I'm building for my Jr. High students. The flat-Earthers aren't necessarily stupid people, they just have a belief that is...well...stupid. I want to show the students that smart people can believe dumb things and give them some thinking tools to ensure that they don't become one of them.

I don't even know what to say, I don't think there is a word for how stupid thinking the earth is flat.

Religion is based on a possibility. Flat Earthism is based on a proven impossibility, and reliance on conspiracy theories and evidence denial in a vain effort to make that impossibility possible.

I would liken Flat Earthism to Young Earth Creationism: the notion that the universe was literally created in 6 days, and that its age can be calculated by running through the timeline of the Bible. Both are demonstrably nonsense. But this is a relativelty recent bit of bonkers. Most Creationists worldwide don't believe that the Earth (and indeed the universe) literally took 6 days and nights to create.

I can prove that the Earth is flat using the Bible (old and new testament)

How do you not know that Earth is an oblate spheroid?

If you are trying to prove your case with photos, then YOU need to step up YOUR understanding.

Its really easy once you spend some time studying the subject.

eg. "Why can't people in South America see the Pole Star" ?
"Why do the stars rotate in opposite directions at the Northern and Southern hemispheres."

Easy.

Although that's true I don't see the point in talking about it, or even arguing with them.

Imagine if you tried that tactic with someone obese, who is eating junk food. You can lecture them all day about eating organic, whole food and taking daily walks but they don't care, and will never do it. They like their lifestyle and are comfortable with it.