Anyone knows you cannot argue with a drunk or a religious fanatic, and it is the same with this denis, so I agree that they should be just ignored.
There is always hope. I know many staunch Liberals who have become sensible, and very few that have gone the other direction. Some remain children all their life.
A most interesting person was one who started listening to Rush Limbaugh because he was curious about the evil Rush. He is one of Rush's great supporters. He was,actually, deceived by his loved ones and friends, but they meant him no harm.