Has nothing to do with lobbyist. Has to do with simple facts. We do not traditionally receive gas or diesel in large quantities. We get oil. From that we refine the oil for whatever application. When we make gas, a byproduct is diesel. So we end up with an excess of diesel since no one here buys diesel. We can't just hold more and more diesel indefinitely.
It's all market. We as americans don't like diesel. Not everyone obviously but most of us don't. Whatever that reason is(sound, smell, complexity, cost, availability, etc) can be argued but that is the fact.