I didn't read the whole thread, but I'm wondering how hemp = gasoline alternative.
I assume they'd use it to make ethanol, like they currently do with corn. The process works, but I guess corn prices have gone up too much to really be financially successful. So really, hemp = corn alternative? If that's what you're saying, I don't think they'd legalize marijuana just so they can grow it for commercial biofuel use since apparently they already know what the best thing is to grow for biofuel. It's some injun plant called switchgrass.
Anyway.. marijuana should be legalized for a lot of reasons, but probably not because of the one you posted about.
Not to mention Hemp and Marijuana are two different plants.