It's about not wrecking somebody's teeth by confiscating their pacifier while they're rolling. It's about not causing overdoses by limiting access to milligram scales (because trying to use a kitchen scale to measure a dose is dangerous). It's about creating an environment where people won't lie to you if you express concern about their habits.
Most drug problems are poor dopamine hygiene or mental health issues of some other kind. Let's focus on that instead of celebrating that somebody is "off the hard stuff" while the root cause remains and wrecks their life through a video game addiction.
If you're not seeing the harms caused by overbroad vilification of drugs in general it's because the people around you who are struggling with a substance problem are hiding it from you due to your attitude about such things. And if they're hiding from you, you can't help them.
Hard drugs are dangerous and I’ve seen a lot of people get burnt thinking they can abuse them freely. From time to time I burn myself as well, but have a penchant for stove touching, probably related to the accelerationism thing.
I have a lot in common with your cousin: I had long hair, I skated, I had “out there” beliefs that my family encouraged or at least tolerated. My community typecast me as a pot smoker or a punk or a hippie, when the time came to it, I was like “hell yeah I’m gonna get high, everyone already thinks that I do anyway!” Unfortunately that set me down a bad path, and I’ve been insanely lucky and dodged a lot of bullets that could have severely fucked my life up.
For what it’s worth, my parents did a great job of saying “we will absolutely not tolerate you doing drugs, but we will give you the freedom to do your thing, and when you fuck up, we will ground your ass into oblivion.” I think that having that as a threat gave younger me a lot of good reasons to think about what I was doing and to do it in a more responsible way than some of my friends whose parents were more hands off with things.