Invariably big companies are causing some harm as a side-effect of their business. They’d usually be better off if their business didn’t cause this harm. This means they employ people whose entire job is to reduce the harm. If your goal is to make the world a better place, these roles can be a good opportunity to do that given the scale involved. From a utilitarian perspective, it’s easy to argue that a person in that position is doing more good than most people in the world.
On the other hand, if someone is just trying to make the most money, they may end up causing harm. There are many jobs like that - but the scale is more at bigger companies.
I don’t think it makes sense to judge someone based on the company they work for if you don’t actually know whether that individual’s actions are making the world a better place or a worse place.