I've also learned this lesson the hard way through more experience than I should have contributed towards it. If someone values reason and evidence, they will probably not stay on the right. I was raised in a right-wing environment and had right-wing beliefs when I was a teenager, but I was always curious to know as much about things as I could find out. Losing my faith in right-wing ideas was inevitable in my opinion since most of it depends entirely on its adherents not investigating its claims whatsoever. I will absolutely talk to a young conservative that knows me face to face and I have had productive conversations like this, but there's no helping the adult true believer until such a time as they seek to be helped (and even then it's most likely a bad-faith ploy but I'll still take the gamble even though I've never won). It just has to be exposed and opposed.