From what I see, the Buddhists were communist, and had very legitimate position against the Diem crowd that was corrupt beyond belief. And of course the ruling class was Catholic, it was a former French colony.
It just seems unreasonable that it should run as a French colony did, with the majority Buddhists being under the thumb of the minority who gained position via the French.
Make that the Buddhists were NOT communist and had a very legitimate position against the Diem crowd.