I'm assuming you meant "the government has NO right..."
I agree with that. 100% I don't think the gov't has any right to know that.
It just seems to me though that if you put this info down on a legal tax document, sign your name to it and send it off to the IRS, you're agreeing to play the game by their rules. If you put down 'I earned $50,000' you just told them your income. All the deductions from that point have to be legal ones. Otherwise, you're knowingly commiting some sort of fraud and they can nail you because you told them how much you made.
Now, if you told them you made $0.00 then they'd have to go and prove you actually did have an income. It just seems to me if you list any income at all, you're giving them all the evidence they need to bust you.