They are kept desperately poor by lack of other available work, and forced to accept starvation wages, and when they attempt to organize unions, the corporations hire mercenaries (paramilitaries, or "death squads"
who terrorize them, follow them, send death threats any number of ways, even get on their buses taking them from the plantations to their homes, before they start getting deadly serious, beating, multilating, then finally murdering them. U.S. corporations have been sued for their part in these atrocities.
It was illustrated in stark terms when one of the workers who lived in a house surrounded by tropical trees was so sick from his pesticide-delivered disease he would run out of his house and vomit outdoors. At some point, parrots who lived in the trees above them actually picked up the sound of vomiting themselves and would sit in the trees and fly around sounding as if they were vomiting. I could never forget that, after reading it the first time.
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