I am missing the argument here -- its better to legalize than not legalize, but you are against legalizing? To level set, I don't think many people believe legalizing will make everything rosy. I believe instead they think it will improve the situation, and optimistically free up resources used for criminalization that may be better used for treatment, i.e. instead of training someone to be a cop you can train them to be a nurse.
No.
Look a couple of posts up in the thread you're responding to and you'll see me say:
"I'm 110% for legalization, but we need to set realistic expectations."
and I was responding to someone who was saying that if we legalize there'd be no overdoses. That's just wishful thinking. We need to legalize but be realistic about our predictions about what legalization is going to look like. No overdoses is not achievable (see my other posts in this thread as to the reasons why). But overdoses will definitely be reduced.
A similar state of affairs is likely to occur with legalization of other drugs, though fortunately most of them are much less harmful than alcohol.