The US has laws against bribing foreign governments or officials. You can be punished in America for it, adding an extra layer of risk on top.

Considering this sort of corruption is required to do business in these places, it effectively bars Americans from competing.

The idea behind it is if we don't incentivize corruption, it will go away. Needless to say, it didn't work, as it takes only one person to spoil it. It's a prisoner's dilemma game where only some players get punished