It seems so hopeless at times at the beginning, and the beginning can take years. Your parents are not just hard headed, they are scared because it means accepting a totally different worldview than what they believe in. (This is why we are all conspiracy theorists to the sheeple, when they are the ones who really believe the conspiracy.) When you really REALLY honestly believe you are right things that go against your beliefs HURT you and you dont want to accept them. You even actively seek out justifying your views. And sometimes when you start to believe that what you think may not be true, you even shy away from researching more into it. Everything I'm saying is based on my own experience and how I finally woke up.
But truth and persistence is the answer. Eventually when you feel defeated and your only option is to accept that what you believed was a lie, you slowly come to terms with the truth. This is the first crack, and the most important crack in my opinion. Once this happens, you instantly put more faith in the person(s) who planted this idea into your head, and you are more accepting of what they have to say. Then as you remember the other things that have been planted you are more open to accepting the idea that you could also be wrong about those things too. And plus, the first time is the toughest of discovering you have been lied to, betrayed, and violated. It's pretty damn painful and angering, and this is what they dont want to have to accept. What I'm trying to say is it's easier to accept this feeling as you discover this about subsequent truths. Eventually you become angry as you connect all the dots. This is is when you awaken and things all of a sudden fall into place and make sense.
You must pound away. I like that sledgehammer analogy. I guess this method *may work, but it sure takes allot of time and this methodology is very hard to change if thats the kind of person you are, but eventually things will sink in and they will come to terms with the truth. I pray your parents come around soon.
I think the hardest thing for me is the social aspect, in your circle of friends and family, because once your awake, you dont go back. And if you dont go back their will be many differences and disagreements, and mocking... But you know your responsibility.