The principle that human nature, in its psychological aspects, is nothing more than a product of history and given social relations removes all barriers to coercion and manipulation by the powerful.
If the principle is, Let's not get lethal substances out to the public, the first one you'd go after is tobacco. The next one you'd go after is alcohol. Way down the list you'd get to cocaine, and sort of invisibly low you'd get to marijuana.
Language is a process of free creation; its laws and principles are fixed, but the manner in which the principles of generation are used is free and infinitely varied. Even the interpretation and use of words involves a process of free creation.
The Bush Administration do have moral values. Their moral values are very explicit: shine the boots of the rich and the powerful, kick everybody else in the face, and let your grandchildren pay for it. That simple principle predicts almost everything that's happening.