Well my very amatuer answer would be something like this:

Since smoking usually leads to laziness and sleeping, people just assume that those "burnouts" are going to be lazy and sleepy forever. People fear what they do not know, so even though most have no understanding of what shit spews out their mouths, they still say it. It's just a repetition of myths passed down. Whether than trying to find out something for themselves then making a judgement, it's easier to just follow the crowd.

Now who's the lazy one?

my :twocents: