MOA—The U.S. and its allies are hostile to China. Threatening to cut its oil supplies is probably the most powerful tool in their box. Any alternative supply routes for China make this tool less powerful. The idea then is to prevent the possible use of these routes.
Since its foundation after World War II Myanmar was ruled, sometimes more sometimes less brutally, by its anti-colonial military.
The first U.S. plan to gain control over Myanmar was to install a ‘democratic government’ (sic) that would do its bidding. In 2010, under pressure of U.S. instigated color revolutions, the military conceded to allow a civilian government but kept much of its constitutional and economic power. In 2016 the U.S. preferred candidate Suu Kyi, the daughter of the former military leader and Father of the Nation Aung San, was installed at the head of a new government.