Most of those christians were also raised in a household that promoted this. They are brainwashed into believing it.
It's not a matter of age, Those kids that are innocent will grow up to be those radicals you hate.
To be honest these people are clearly disgusting and are the ones who deserve everything that they say others deserve. I know it makes me just as bad for saying that but it's true to be honest, at least I don't hate and detest people for how they differentiate to me.