Even if they’re the most evil corpo ever, the buyer is still the government. If a democratically elected government buys this products, I would assume, in large scale of things, the general population wants the most evil corpo.
It’s not like they are overthrowing South American countries for favorable terms in pineapple and banana trade *cough*Dole*cough*Chiquita*cough*
Yet.
This works is if-and-only-if you assume everyone involved is a good actor. In fact, many if not most in politics are bad actors, and voters largely believe said bad actors.