Diem was trying to impose Catholicism on a country that was still primarily Buddhist, it’s no wonder that the South Vietnamese government was never particularly popular and that folks weren’t particularly motivated to fight for it.
The way I heard it was that the Viet Cong thugs were being supported by the Buddhists, so sure - he may have dealt harshly with their support group. He wasn't trying to impose Catholicism, he was trying to survive.
And yes, JFK should never have allowed the 'hit'. Never the great leader of 'Camelot' that the Media created.
Now you’re in trouble. T