Ummm... Lets talk about the pro's of those subjects you've chosen:
First, lets touch on Drugs. What are the pro's of those: Shortened life span, reduced health, addicition, expensive, and lets not forget everyones favorites, overdosing and sudden death.
Next, Alchohol: Liver Cancer, Cirrhosis of the Liver, Adiction, Reduced inhibtions leading to poor decision making (possibly leading to the usage of Drugs, premarital sex, and killing others with your car ect)
Premarital sex, now here's a gray area: If you're smart, you should be ok (If you can't protect your rocket, keep it in your pocket, if you know what I mean), but there are risks to that as well, like unexpected pregnacy, STD and other lovely things
Oh wait, those aren't pro's, those are cons. It just might be that there aren't any pro's to those subjects.
Speaking from "First hand experience" as you put it, I'd much rather been informed about something before diving into it then walking in blind.
Me thinks you just don't like those PSA's
And I don't think they are unbiased, since they are discrediting a point of view, which makes it very biased. But lets look at what those are talking about: The ones you mentioned are not very healthy or safe lifestyles, and all of them can kill you if you're not careful (except school, but then again, are those safe anymore? but thats a discussion for another time).