Great post shadowsdarknes.
Sometimes the perception of the movie, that it's too over sentimental and schmaltzy and the Pulp Fiction/Shawshank backlash (which is just 3 great movies), eclipses my last viewing of it. But I watch it to ending almost anytime it's on tv. Its just so well executed, and I've come to really love it.
I understand you could perceive it as a condemning of a rebellious life in Jenny, but I think it really was just a tale of an isolated incident. It's certainly happened before that drugs and abuse have taken someones life, and I think it worked really well narratively for Jenny. Just to contrast Forrest, as stated previously, adds another layer to the story. It makes it a bigger film than it would have been otherwise in scope.
Mostly the best shit of the movie though, is how Forrest communicates with Jenny and Lt. Dan throughout the movie. It plays pretty brilliantly on the surface as a very direct charmed life comedy of hilarious historical significance. (kind of like Norm MacDonald-lite in directness "that's bad" "that's good" prose) But the movie really excels as it hits another layer of complexity, when it comes to a few specific people in Forrest's life and their issues. Also, how through events of grand historical significance, Forrest keeps perspective with a shocking amount of reverence for Momma, Lt. Dan, and Jenny. When any of them need him, he's there. It constantly pulls it back from its larger scale story, to keep focused on his relationships. Which Forrest understands as important to him. Forrest is never as distraught about political events, as he is about what Jenny might be doing. There's obviously depictions of lifestyles at work, but I don't think it's a political movie at all. It's got about as much real political intent as Back to the Future or Roger Rabbit.