bottom line:
-like many other people mentioned, exhaust may be illegal in your area despite the rather deceptive "50 state legal" clause that only refers to federal standards, and not individual states, cities, and etc.
-and since you are using an illegal product, accept the consequences and don't complain.
-if you don't like the law, it's your fault. you can petition to change it. However, if it is already illegal in your area, i doubt you would get much support. we live in a democratic republic afterall, so it's your responsibility to enact change.
-and if you don't know the law in your area, it is your responsibility to find out by taking a quick trip to police hq or city hall.
-yes, it may seem unfair that they only ticket a hand full of illegal fart cans and tinted windows and etc., but that's life. they can't enforce everything. hell, cops can't respond to every jaywalker there is. but laws are laws, and we must do our best to stick by them.