If a government sanctions and protects opaque private theft through the fractionally reserved fiat banking system, they lose the legitimate standing to collect taxes. If you won't defend the citizens' interests by preventing the bankers from robbing them with inflation, don't expect the citizens to respect your authority to tax them. 

Legitimate taxes are compensation for effective governance. Protection of property rights is the fundamental basis of governance. Fail at that, and your legitimacy as a government is gone. Taxation by an illegitimate government is just extortion by well organized criminals.