professor How many times must we review, with American citizens that the POTUS doesn't control the cost of a barrel of crude!
Strange. The graph shows a strong correlation. Let's see - what is a better support for an argument? Data that shows a correlation between an administration period that entered office with a stated goal of making the U.S. energy independent, or professor's proclamation that the price of crude cannot be manipulated by the activities of the world's largest oil producer and consumer? It's not the rule of demand, but of supply and demand.
One president came in with a goal to make the U.S. energy independent, the other came in with a stated goal of transitioning to clean energy as soon as possible. One has the natural impact of reducing energy costs if implemented and the other has the natural impact of raising energy costs by utilizing less efficient (currently) means to produce cleaner energy. You and many others don't like the other consequences of cheaper energy, but that doesn't mean it can't be influenced by the U.S. president and their regulatory control of the industry just because you don't like it.