This mostly has to do with government policy. It seems like wherever there is a loophole, somebody will use it. If companies can find a way to take advantage of a law or policy, then they will. Their main goal is to make money. That seems to often be the goal of politicians too, personal gain. Often these businessmen get together with the politicians and come to agreements where they both get richer. The politicians of rich countries make laws that let the businessmen pay less taxes or receive different subsidies. The politicians of poor countries make laws that allow (often) foreign businessmen to take advantage of their resources and people. For this the politicians get some cut for themselves. It mostly comes back to corruption.