Consider this
Of course Supply and Demand are manipulated. OF COURSE. And the effect of that changes the Supply or the Demand or both. IT DOESN'T CHANGE THE LAW it changes the outcomes. All the things that "muddy the water" simply change the supply or demand of something in the equation. Think of the quadratic equation in algebra. Changing its x and y values doesn't invalidate the equation, it simply changes the outcome. In the same way, actions and policy can change the values of Supply and/or Demand, but not the equation itself. When the Hunt bros tried to corner the silver market they affected demand, thus driving up the price. When the demand was taken away, prices crashed exactly as they should.