I think rational debate is certainly in its death throes. I have had people demand I provide evidence/studies/whatever to back things up, and then outright refuse to read them when I have done so. "I don't need to read that!!!" So what do you do with that?
No worries, Brother! An unteachable person is like the proverbial thirsty horse that you lead to the water and won't drink because it wasn't it's idea to do so or because it didn't find the water on its own terms.
Some people simply don't want to see the light and choose to remain in the darkness.