I'm going to have to agree with GreenGauncho, just do your best to politely explain your feelings towards your parents.

I find religion interesting and yes there is a scam/power-hungry aspect of it but there is also something beautiful about it. I don't think people rip people off and kill people because of religion, I think its just their nature to do so and religion is a convenient excuse. Outlaw religion and people will still be doing horrible things.