Ought to be is the way it is. Firing an employee because he discusses his salary with other employees is illegal. You are free to fire that person, but you should expect a lawsuit.

And did you really link to a tutoring lesson about objective and subjective statements to 'prove your point'? What a useless thing to do. Your knee-jerk anti-establishment opinion about how the world works, based on your limited experience is not a good bellwether. (http://dictionary.reference.com/browse/sophomoric); shoot the messenger if you like.