Constant pain can produce mental illness and negative, hateful thoughts. Again, look at the bitter, angry assholes on JPP and look for similarities: Elderly Euro-culture "Christian" males.
I wonder if Luther started to suffer clinical paranoia. It's not just that he thought the Jews were wrong, stubborn, liars.
He began to think they were mouthpieces for the devil.
Which is how Luther started to think about the Pope too.