There is no point in responding to such nonsense.
Someone who responds in such a manner is not looking for rational discourse, and not giving you any actual advice. They are merely saying that their value-system is such that they do not want to hear any criticisms at all about their country, culture or government.
The proper response is a punch in the mouth or, if you don't fancy an assault conviction on your record, to simply ignore the person.
Edit: As an aside, another warning sign that he's not someone worth talking with is that he can't distinguish between something being illegal because its wrong (ie theft) and something just being illegal because a lot of people say so (ie not paying your taxes.)
Social metaphysics, anyone?