I think that most people of that age (early 20s) see themselves as indestructible. (Not all of them, I’m sure.) They’re finally free from the rules of mom and dad. No one can tell them what to or not to do. Screw any “old fart” rules! They make the rules now. Finally, they can drink that long forbidden substance called alcohol (legally) and they’re going to do it forever. They don’t have many responsibilities yet to tie them down (family, job), their bodies are young and sexy, so now’s the time to live it up and party hardy! The world calls to them (just look how the media portrays people their age). While they may think they know everything, they haven’t had a chance to develop any wisdom.
In other words, yes, they are that stupid.
Shuhak 