Why did the u. s the french in their fight against hochiminh?

The US was certainly anticommunist and certainly a French ally but it is described in Bernard Fall's "Hell in a Very Small Place" as a gradual process.

the option which was not a function of missionaries in the northwest was the first one - they established posts for trading furs and other goods.

missionaries were sent around the world to spread religion and their knowledge and others - they were not merchants who sold furs and other goods.