There is another reason. Probably not a direct cause, but it does merit mention: stabilizing the global economy.
When the world's economy is dependent upon the most politically unstable region on earth, bad things happen. The bulk of Middle East oil gets shipped through the Strait of Hormuz, a narrow passage between two antagonistic countries; Saudi Arabia and Iran. It would be very easy for one of those two to close that to maritime shipping, plunging the global economy into recession. The constant presence of a US carrier battle group in that area is one reason this hasn't already happened.
The less the world depends upon that narrow passage, the less the impact of a disruption of Middle East oil on the global economy, which also means fewer armed conflicts. Most of the major conflicts of the last 30 years have involved the global oil supply. That's why the western nations intervened in Libya, but not Rwanda.
This also holds true when another major oil supplier, Venezuela, plunges into political chaos.
If the US plays a major role in global energy production, the end result is a more stable energy supply and a more robust global economy, which is good for everyone, not just the US. If one looks beyond the over the top hyperbole in current US politics, the differences between left and right are fairly trivial, when compared to ideological conflicts elsewhere, or in the past. It is a politically stable country.
Being a major oil exporter also makes net importer nations more economically dependent on the US. That is political and economic leverage, which may come in handy in other areas. If another major power that is almost totally dependent upon oil imports starts muscling its neighbors, fear of having its economy torpedoed by a restriction of energy supply can keep it in check, without a single shot being fired.