Behold my opinion!
Having modded on other forums, twitch channels and discord channels, 13+ is a very common age to set as an age limit. Generally, mentions of drug use are allowed there, within reasonable context, and almost always carefully monitored to make sure it doesn't get out of hand.
Coincidentally, a PG-13 movie rating is also where drug use starts getting permitted. So should we ban it on here altogether? Meh, probably not. It's allowed literally everywhere else, and even I as an innocent soul knew that this concept existed when I was 13.
Is having a thread celebrating the concept okay? Definitely not. But the thread people keep referring to isn't 'drugs are cool', it's just full of people virtually high-fiving each other for having a common interest and wanting to be friends over it.
Going by the rating enforcement that was taught me, I don't see anything wrong with that! If the topic is allowed (within reason) then it shouldn't be much different from me going "I like gardening, I want gardening friends! I think bees are the coolest. So, anyone here also love flowers?"
As I said up near the top, these things are normally watched to make sure they stay within acceptable limits. If it wasn't okay, someone
will intervene, I'm sure.
But I guess that's not my problem here. I ain't a mod.