Ask Galileo Galilei about it. The Catholic church refused to accept his evidence regarding planetary orbits, and the equal acceleration of gravity. He spent his final years locked up for his 'heretical' views.
Nowadays, Evangelists have taken over from Catholics. For example, in insisting on creationism. (The catholic church accepts evolution.)

It does seem rather stupid when you look at it. Remember also that it was once said that "if god wanted you to fly he would have given you wings." Trace this back to early beliefs of angels having wings and they could also fly.

And humans haven't had a good night's sleep since.