I'd say alot of us spent our youth in a daze. If ever anyone needed to be in a daze it would be those in pain from dying. If smoking weed gives them relief and some giggles along the way then whats it to you or me?
Because people are unable to exercise their Rights in the manner intended when they are under the influence of narcotics. And that is why your rights under the Constitution and your 'right' to take recreational drugs are mutually exclusive.