Stop being a spoiled bitch for starters. You live in their house, have the decency to at least talk about the problems that are obviously concerning them and is their business so long as your living in their house.
Treating your parents like shit by saying, "it's my private ritual" won't do anything but upset them--

If your parents are adamant about keeping you away from drugs, talk about it and then smoke out of the house or when they're asleep.

If their willing to listen, talk it out and explain things to them.

Jesus, guys-- I'm still in college and even I can tell that this behavior is inexcusable. Cut that melodramatic shit out about parents buying into the government's lies and all that shit-- maybe, MAYBE their concerned about you? Maybe they care about you and don't want one thing to lead to another? Ever thought of that? Nah, probably not since prior to this whole thing, you were stoned 24/7 as you so eloquently put it.