Where do you live? Because growing up in the Netherlands I can say all the negative side-effects were very clearly explained to us in high school, without stigmatizing it.
EDIT: it is a sincere question - obviously the Netherlands is in a kind of special position here. And my experience is from the late 90s, so who knows how things have changed since then too.
This goes back to the root comment in this thread that people see this issue as very black and white.
The lightest strain in a coffee-shop was pretty strong.
But with that said, yes, we do. I even know someone who had it, and they quit using weed after that. It's kind of treated like the complicated thing that it is: genetics and existing mental and physical health are all risk factors, and as a teenager there is the still-developing brain to consider (just like with alcohol). You basically have to decide for yourself if all of that seems worth it.
I've never seen this attitude in the wild. In fact, most heavy cannabis users I know express a desire to use less.
I wonder where you are from. If not from USA, you've been misinformed. If from USA, stop assuming you're the frontrunner of anything please.
It's good actually, because it's the young mostly, and we're out of jobs in my country... more jobs for me!
Not to mention that it is almost always mixed in with a little tobacco which is a smell I can do without.
(Note: I don't have a horse in this race- I don't use marijuana because I don't like the effects, but I'll be the last person to act like it's some demon plant out to hurt capitalism's productivity.)
On a more serious note, cynicism is one way to fail to cope properly with reality, not something that gets you far and high in life. But hey, more jobs for us positive folks compared to bitter sad cynics!