I'm pretty sure he was a Lutheran. He was a mathematics professor at a seminary school and was highly motivated throughout his career by his religious beliefs. Maybe I missed something there, but a few sources I looked at said his first inclination was to become a minister.
You're right in that practically all of those guys' works were rejected by the catholic church and many were accused of heresy. You'll never find me defending the catholic church. DoK made a throwaway statement about Christians perpetuating ridiculous and erroneous scientific views throughout history. I gave a simplistic response stating that many of the biggest breakthroughs in science were made by men of faith. I was basically saying he was right, but that it goes both ways. Overall, I think it's a moot point.