World currency factors have a huge impact on commodity prices, since a relatively strong dollar makes commodities more expensive for overseas purchasers. The recent currency adjustment by China has had a huge effect on prices because of the size of their market and the abruptness of the devaluation change.
The end of the upswing phase of the commodity price super-cycle after its peak in 2011 has lowered economic growth prospects in most of Latin America. While that broad statement can hardly be disputed, chapter 3 of the latest IMF Western Hemisphere Regional Economic Outlook called attention to underlying significant differences among countries in the region.
We can just make stuff up with aplomb. One day we say the market rises as "investors cheer" good employment numbers; the very next day we attribute the decline to "structural problems" and look forward to a long decline! Were those structural problems not present yesterday when investors were cheering?