Yes, yes it is. It is exactly hypocritical. He just said that rich people should pay more in taxes. Then he decided not to pay more. If he said that he himself SHOULD pay more but then he doesn't, then how do you think that's not hypocrisy? He is not doing the thing that he believes people in his position SHOULD do. His excuse is: cuz THE LAW®
Hypocrite: "a person who pretends to have virtues, moral or religious beliefs, principles, etc., that he or she does not actually possess, especially a person whose actions belie stated beliefs."
Something is hypocritical if you don't do what you say that other people should do. Because the law currently doesn't require you to do that thing doesn't make not doing the thing you preach to be non-hypocritical.
Yes. Yes it exactly makes them hypocritical. If you try to force other people who aren't you to pay more money for work, and then you personally try to pay less money than that, it exactly makes you a hypocrite.
If you say people "should" do something and then you do the very thing you "souldn't" do, then that is being a hypocrite.