To try to get the government to regulate between those two Cannabis would take a lot of resources to make sure that only the "industrial" Cannabis is allowed.
The more efficiency way is just to ban them both outright.
I don't think either variety of hemp should be illegal. I wouldn't touch narcotics with a ten foot pole; but I don't believe in prohibition either. Marijuana and other drugs should be legal the same way alcohol and tobacco are legal. If both varieties of hemp were legalized, then the black markets would be crushed, marijuana would be less lucrative, crime would be reduced, Federal spending in the war on drugs would go down, and American manufacturers would be given access to industrial hemp all in one fell blow.