My impression is that the current administration in Brazil really does not care at all about deforestation, and hasn't been the best at respecting contracts, so refusing to buy is more likely to work.
Considering that the Amazon is pretty essential for the global environment, this strikes me as an aggressively reasonable approach.
These are fanciful ideals, but where the rubber meets the road, there are real tradeoffs with real consequences. The best we can do is make sure that we apply incentives to ensure that people do the "right" thing.