It's not absurd. It's your body, you can do what you want with it.
There's been plenty of evil done by do-gooders, who are so certain in their rectitude about what's best for others, that they feel justified in imposing that rectitude upon them.
> It's your body, you can do what you want with it.
I can’t hit people with it, I can’t transport it onto private property, I can’t use it to yell all night, I can’t sell organs, the list is endless.
Anything we do, we do with our body, and every law ever applies to what I do with my body. The question is: do we think the costs of law the restriction outweigh the benefits? You may think so, but you have to argue for it, you can’t just invoke a principle which has never existed.
In case you aren't, being able to do what you want with your own body does not include a right to harm others. Remember, we are talking about ingesting drugs, not hitting other people.
But it allows for an increase of the frequency at which those crimes are committed - at which point it’s too late. Sure, can punish the criminal afterwards, but the victim has already sufferred.
> In case you aren't, being able to do what you want with your own body does not include a right to harm others
You have to make the argument that drug use doesn’t harm others. In a libertarian thought experiment maybe it doesn’t, but in the real world it does.
In particular, we tend to criminalise behaviors that increase the risk of harming others. Consider drunk driving. Nobody is harmed if I don’t have an accident. But the risk of an accident increases, so we criminalize it. The same is true of hard drugs. The probability I will harm others conditional on meth addiction is higher than the background probability.
When you start using eg meth, you open up, with reasonable probability, a whole host of other externalities beyond impaired driving. (The same is true of alcohol, except with far lower probability, which is a key disanalogy.) Hard drug users commit property crimes and violent crimes at a much higher rate than people who don’t use. Crime increases during binges, suggesting causality. But you really don’t really need academic study to demonstrate causality here - it’s obvious that people steal to fund addiction.
And yes, you can prosecute them for whatever property or violent crimes they commit, but for the victim, it’s too late! They have already suffered. A better outcome is if we decrease the amount of usage of drugs like meth and fentanyl via law enforcement, and subsequently decrease the externalities that society has to bear.
Intent is less clear, and even if prisons in the US were much more humane, addicted people would need extra resources (including human effort) to break the addiction and hopefully prevent further incidents. Really, addicted people are a liability because they'll do pretty much anything to get more of their drugs (and they're often violent); it's just a matter of how prevalent this has to be to be a serious issue. Of course, they're not solely responsible for pervasive drug usage.
You are your body. You don't have the right to do what you want to yourself. That's your assumption, not a self-evident truth. The very idea that you can do absolutely what you want to yourself is incoherent. It undermines the very basis of morality. You're effectively saying the objective good doesn't matter. What matters is what I want to do. That annihilates all morality.
I also said nothing about do-gooders. I never said I supported do-gooders. What sorts of legal measures ought to exist is a prudential judgement. In this case, it's clear that drug use should be criminalized.
There's been plenty of evil done by do-gooders, who are so certain in their rectitude about what's best for others, that they feel justified in imposing that rectitude upon them.