I'll agree but sooner or later everyone is going to make the leap its just a matter of how far they think the fall is.
Say we start thinking about weed the same way we think about alcohol now. Ok but there is molly, mushrooms, LSD, and ketamine that can all easily step into the space that weed had occupied. Say we discrimininlize all that too. Now people understand how mood altering substances work and aren't afraid them. Does heroin seem more accessible now?
I'm not saying a tier system is good and maybe society is just fundamentally flawed in the way it thinks about mind altering substances. Some how though, we need to show people before they learn the hard way, that substance abuse has lasting adverse effects including death.