I was paraphrasing your argument to put it in its generic form. Here's what you said

So they're "too intelligent" to "believe that all drugs should be legalized". So I suppose I and those like me are therefore insufficiently intelligent because we believe the government has no place regulating the consentual activities of adults. What should the government proscribe next "for our own good", to help protect us helpless little lambs? Eating poorly and not exercising is probably not as short-term lethal as a meth overdose but affects a much larger segment of the population - perhaps we should have the government regulate our diets and force us to exercise "for our own good".

I think it should be 100% illegal for me to FORCE someone to take crystal meth, but I don't think it should be illegal for ME to take crystal meth - although I do think it would be stupid of me to do so.

While I'll grant you there are not likely many "high-functioning" crystal meth addicts out there, there's all kinds of things that will hurt you if you use them wrong. Nowhere in the Constitution does it say that the federal government has been granted the power to protect people from themselves and as the 10th Amendment makes clear, any powers not *specifically* granted to the federal government are the domain of the states or the people. If anyone wants to criminalize a substance, they must AMEND the Constitution in order to stay within the rule of law (See: 18th Amendment) and even then it can turn out to be a miserable failure (See: 21st Amendment).

The solution to crystal meth zombies is education and treatment, but ultimately you can't criminalize suicide.

But then again, the fact that I feel this way demonstrates my lack of intelligence.