Considering that you're a Teen yourself, you might want to wait till you're a bit older and have the benefit of hindsight before passing judgment on your own age group.
You also have to understand how the News and entertainment media works. You hardly see anything about the good being done in the world, but every time something wrong or bad happens, it dominates the news cycle. Anything that deals with Teens and sex drugs and crime, it'll be on the news. The news will actually make it sound bigger then it actually is. Kinda like "The smaller group giving the larger group as a whole a bad reputation".
In entertainment, the adage "Sex Sells" comes to play heavily. Writers are willing to do anything to make a good story so they can make a living.
And since we live in a society where our everyday lives are influenced (Whether we realize it or not) by what we see/hear in the media (TV/movies, print and radio), it all comes down to personal choice of whether or not you want to act in that way.
I bet if you took a good hard look at your fellow classmates at school, I bet a lot of them actually do have morales and are actually the opposite of what you described.