There are different kinds of oil and shipping costs that must be considered. It may be more efficient (profitable) for an East Coast refinery to import crude than transport it from Alaska. Furthermore, the decisions to import or buy domestically are made by the (usually multinational) corporations who own the refineries, not politicians. It's called capitalism.
It doesn't make sense to you because all you are considering is the agenda-laden juxtaposition of statistical summaries. Makes more sense to consider reality.