Companies are not evil, they are profit driven, and they make profit by responding to demand. If people demand evil, they will make evil, if people demand good, they will make good. I think it is too easy to blame them when ultimately, we are the one who support them.
In the case of farming, we want cheap food, and the way to make cheap food is intensive farming, with pesticides and synthetic fertilizers. So, companies make pesticides, farmers use them, and we eat the cheap food. Because we recognize that some checks need to be put in place, we elect governments to regulate all that, and or vote goes to whoever makes the best balance between cheap food, taxes and subsidies, and general health and precautions. This is crucial because cheap food is a matter of survival to some.
So in the end, there are no "baddies", just a system that's not perfect. Also keep in mind that big corporation are made of a lot of people, you may be one of them. I am. Does it make us evil? Maybe a little, but I don't think any more than average, as middle-class, I even tend to think we define the average.