If the Congress doesn't like the practice, then it shouldn't grill Tim Cook but instead, say, pass laws so that this practice would be forbidden. Isn't that their job?
Shifting the burden to congress is absurd. Congress is a finite set of people with finite time to consider tax laws while lawyers for corporations far out number them in time and effort. Such an adversarial system is inherently in the favor of corporations. They should be responsible for following the intent of tax law.
Yeah, designing clear and well-written laws is a boring waste of time. Congress has much better things to do than that. We should just punish people arbitrarily based on "intent" and the shifting political winds.