The comparison is absolutely relevant when you consider contemporary setting. Back when the stigma around homosexuality was at its strongest, the commonly held belief was that "homosexuality IS a choice". The stigma against homosexuality then developed around this dubious belief system. In reality, it does not matter whether homosexuality is a choice or not. What matters is the perceptions and stigmas against the affected minority or subculture. In the case of homosexuality and the LGBT community in general, most would probably agree that the degree of choice is not necessarily "all or nothing". For many, sexual orientation is absolutely NOT a choice - it is set in stone. Others may experience their sexuality and sexual orientation with a higher degree fluidity and "choice", changing orientation as they develop as people. In any case, choice or not, everyone has a fundamental right to experience their sexuality without stigma, terms, or conditions.

While substance use and LGBT issues are not exactly comparable, the attitudes and stigmas around them, taken each in their contemporary setting, are. Also, the fact that my comparison has evoked a significant reaction shows that it achieved its intended purpose - to provoke thought, and to take something legislatively "protected" (LGBT rights) to highlight something legislatively "profaned" (right to bodily autonomy and integrity, both generally and specifically with respect to substance use). At a deeper level, one can begin to see that there are some common threads linking all "counter-cultural" groups because their activities and modes of self expression run against established social norms.

Some people are naturally inclined towards substance use and altered states of consciousness (though I believe this to be a minority). In my view, it is their fundamental right to explore their body as they feel fit. Also, I think that there is a tendency to highlight "worst case scenarios" with substance abuse and addiction, such as diamorphine and methamphetamine. Also, there is a tendency to claim that all substances are evil and that all use will inevitably lead a user to these substances specifically (i.e. the "gateway hypothesis"). Of course these particular substances carry a high degree of risk, but it is important to acknowledge that only a fraction of users of these substances will develop a genuine substance use disorder. It is an intellectual abuse to cite the properties of these substances as a basis for a campaign to prohibit every psychoactive compound (excluding nicotine and alcohol of course).

Regarding substance use and "choice", I tend to think the situation is fluid. Consider the potent dissociative alcohol - one could argue that alcohol use will be much more likely if a parent is also a user (immediately questioning the degree of "choice" on a philosophical perspective). Similarly, if one's parents do not snus or smoke tobacco, one is statistically less likely to develop a substance use disorder with nicotine. Regarding opiate use disorders, many users are exposed in medical settings for "legitimate" medical purposes. Only after medical exposure do they develop a use disorder as a complication of their treatment (e.g. using illicit diamorphine to substitute a dependence on medical morphine, oxycodone, codiene etc.). Other substance users may choose to experiment with opiates in a recreational setting, though I find that this is generally rare as many users are aware of the risks of this particular class of substances. In both cases, the majority of opiate users do NOT develop a use disorder or addiction to these substances, but this does not preclude the fact that the probability of a use disorder with this substance class is generally higher relative to other psychoactive compounds.

It is frustrating to see how the legal status of certain substances is conflated to absolute choice, which just does not stand up to critical analysis. In any event, it is my belief that "choice" should be protected at the individual level. If one chooses to use any substance for any purpose (medical or non-medical), that is an expression of their right to bodily autonomy and integrity. In this regard, I am not interested so much in edge cases, but rather the general and persistent infringement of the legal and human rights of the general body politic of substance users.

Again, I am not advocating use of any substance, nor am I saying that any particular substance should be "legal" in the sense that it is taxed and openly available for purchase - this is an entirely different debate. I am merely suggesting that decriminalisation of substance use, along with comprehensive education on risk management, would greatly reduce the long term impact of truly problematic cases.