We already know the useful "laws" we use are just approximations, e.g. ohm's law, hooke's law, boyle's law, etc.
That's exactly what GP was saying. Modern physics does not pretend to be anything more than a series of useful approximate predictions. A hammer is neither right nor wrong, it is merely useful or not useful. Same goes for Newtonian mechanics, relativity, quantum theory, etc.
Google could technically do the same for everyone on that spreadsheet. Sharing their own salary info would not be mentioned on the official papers as reason for termination, But their accessing/showing the spreadsheet could be grounds for termination upon suspicion of gaining unauthorized access to HR systems.
The problem is that judges aren't retarded, and if google fired a significant number of those people, they'd have an unwinnable class action suit on their hands before you can say "nine digit settlement".
That's the benefit of doing it en masse -- no plausible deniability on their part.
You've all probably seen it before, but in case you haven't, here it is: http://xkcd.com/1357/
It's about free speech, and how some idiots think free speech means you can say whatever you want without any repercussions. Of course that's not true, as Randall points out, the first amendment just means that the government can't persecute you for simply having an opinion, people however are free to react to you however they want.
However I've noticed this comic being posted by people solely as justification for censorship or as a simple reply to a complaint about censorship. Instead of making an actual argument for censorship specific to the situation at hand they post this... but what does the comic say then? That the most compelling thing you can say for censoring is that it's not illegal to censor? Ironically this is a mirror image of what the title text of the comic says about defending your argument with free speech, only you're defending your censorship with the lack of free speech.
Person A censors Person B
B: "Freedom of speech! It's literally not illegal to say something so I should be able to say what I want without repercussions."
A: "XKCD comic! It's literally not illegal to censor you so I'm going to censor you."
And no one gives any legitimate arguments for justifying their actions or opinions.