>>201608
There's actually a reason for that. The "comics code" which most mainstream comic book publishers adhere to, restricts the content of comics.
For example, drugs and alcohol (as well as other "vices") must be portrayed in a negative light.
The "good guys" must always win over the "bad guys"
If someone commits a crime, that crime must be portrayed in a negative light, and the perpetrator must be punished for it (whether it's the Hero or the law doing the punishment)
...and the list goes on.
And nevermind the fact that "don't do drugs" ads are a great way for comic companies to make their violent stories more accepted by parents. It's like the old GI Joe cartoons: A half-hour of people shooting at each other and blowing things up is suddenly made "OK" by one of the Joes telling kids to stay in school or not to paint graffiti at the very end of the episode.