Except banning heroin clearly didn't work so well! There's still a lot of people using it. And the profits from selling it go to criminal gangs. And the people using it often die due to inconsistent dosing.
How do you define "manipulative potential"? If you ban sugar in drinks, do you ban fruit juice too? Where do we draw the line for "acceptable harm"? Personally I don't want to live in a society which bans huge numbers of things.