Dario,
You, and your ranter, fail because you fail to define your terms. "Corporation" exists in many different forms. Subchapter S, 1031, non-profit, 501(c)3 are some examples of corporate structures with wildly differing objectives according to tax law. Then there are holding companies, shell corporations, limited liability corporations, and trusts. All of these forms of business organization can be treated as 'corporations' under US law, but they are formed for wildly differing purposes, from protection of assets from taxation to shielding of personal assets from lawsuits, to charitable efforts, to straight business for profit.
Next, you fail to address the ownership issue. When Google was a private corporation, owned fully by the founders, well, that was that. They alone charted the course of the company (or hired those who did). As long as they followed US corporate law, they could do anything they damn well pleased. Like Jerry Jones and the Dallas Cowboys. It's his team, he can do what he wants.
Once you have an IPO, you now have a lot of owners. They are called "shareholders". It doesn't matter if they own a share for ten minutes, they still have a property right in the firm. Therefore, they have an interest in the running of the firm. They elect the board of directors, through whom they express their desire for running the firm. Now, granted, 100 shares of IBM doesn't give you a large voice in that firm, but you are still interested in IBM making a profit, getting your share of profit (dividend), and having the firm being worth more (higher share price)
What I see from your friend is a desire to curtail these rights, all in the pursuit of some magical form of economic justice. I profoundly disagree with this. Corporate life is a form of creative destruction. Companies like K-Mart came about to provide a low-cost alternative to the Sears and Montgomery Wards. K-Mart was, in turn, undercut by Walmart. Walmart is getting gigged by the Internet. And so forth. Forcing corporations to charge prices that do not exceed some arbitrarily set profit margin removes one of the tools the corporations use in competition with each other.
And who watches the watchers? Who amongst us is smart enough to set exactly the right profit margin? I know, Obama, but I mean in the real world. Nobody. Not even the CEO of Walmart. It is a constant balancing act. Excess profits are the fuel in the tank of the corporation, allowing expansion, arts sponserships, research and development, charitable outreach efforts, merit pay, advertising, and so forth. You limit a company to a 2% margin (just to throw out a number), and poof, there goes the Little League sponsorship, the tractor trailers of supplies given away during Katrina, and the raises for the workers.
No, your friend sounds bitter and angry and ill-versed in capitalism. I would suggest he begin reading Rich Dad, Poor Dad, by Robert Kiyosaki, immediately.