The real question is: Why should it be fair? We don't live in an ideal world, we live in the real one. A "fair" tax rate, even if fairness could be quantified and applied, might very well be a rate that causes businesses to flee the country for more favorable rates. If the goal of taxes are to increase the well-being of citizens, I don't see how driving businesses out of the country en masse with them is an the best interests of the public. I'm not saying that's necessarily the reality, but treating "fairness" as the most important consideration is, to be blunt, asinine. What are the odds, really, that a "fair" corporate tax rate is also the one that results in the greatest well-being of the citizenry?

I would sacrifice economic justice for economic prosperity every day of the week. I simply don't care if someone is "exploiting" me if that exploitation actually increases my well-being in the most important ways, and while a lot of people might disagree with that in abstract, I'm willing to be 99% of adults would make the same decision if actually faced with that dichotomy.