Opiates (including heroin) do not cause brain damage. Marijuana does not cause permanent brain damage (it can impair some functions in the short-term through several months after cessation of use, but not permanently). LSD causes very very minor to unexisting damage. Alcohol causes brain damage. Most people are fully capable of assessing whether the damage from an activity is worth it, a skill that can be better developed with real, unbiased, factual education that does not exist now but would be essential to any legalization program. Furthermore, some people believe the direct and permanent damage inflicted to their bodies when they get piercings or tattoos is worth it, should those be banned?