Why restrict US exports of natural gas?

 The answer, of course, is politics:

To stop the war in Ukraine from disrupting energy markets, [Biden's] administration has overseen a big expansion in domestic fossil-fuel output. As well as being the world’s top LNG [liquified natural gas] exporter, America continues to be the biggest oil producer. That angers the climate-anxious left wing of Mr Biden’s Democratic Party. ...

But US restrictions wont help:

...the impact of the pause on global markets—and thus on global emissions, which is what matters to the climate—will be minimal. Forgone American exports will be offset by fresh supplies from Qatar, Australia and elsewhere. “I think there is an opportunity,” declared Jonathan Wilkinson, Canada’s energy minister, on January 30th.

BOTTOM LINE: President Biden's virtue signaling is worse than empty, as it is harming US producers by shifting US production to Qatar, Australia, and Canada. 

Link to Economist Article