You can say that about every voter too. Except with voters "maximizing profits" means maximizing the benefits to the voter.
That's an interesting angle and I agree with the base, but individuals and corporations differ fundamentally in a few ways and I see you pointed out some of that later on. As stated, an individual isn't beholden to a shareholder, and another example is that corporate social responsibility is a different type of weight than community morals or whatever individuals follow.
I think the key thing we agree on is that 'selfishness' is part of life, and by extension part of economics.
I don't think it is reasonable to distinguish between "corporate" and "individual" greed in these cases.
On a level of scale it is, though. Principles like "individuals and corporations should be allowed to work in their self interest" have a limit. If a corporation owns all the water in a country dying of thirst, there is no principle. I would say the actual overarching principle is "corporations are given special considerations so long as they are perceived to benefit the public good"