How has Monsanto caused harm?
This is a very controversial question. The politics of food (yes politics of food), are complex. As you probably know Monsantos is a seed company and they are very hated by many people. They genetically modify seeds and they claim that it produces a better harvest. This might or might not be true.
They are disliked though by many, because smaller farmers are saying that they are being bought out by Monsantos. Moreover, they are saying that Monsantos is trying to intimidate farmers into buying only their products. What is even worse, they are saying if there is any trace of their seed in a farmer's field, then Monsantos has a share to their crop. Finally, Monsantos has been reported to hire some pretty powerful people to look after their interests.