It says the federal government has the power to collect taxes and lists some reasons for why those taxes may be needed, it doesn't say the federal government can just tax the shit out of everything to pay for each and every one of their little pet projects.
Just like the constitution clearly states that each house of Congress can make their own rules, yet when the Senate does just that Seran throws a bitch fit and says "But the constitution doesn't specifically mention a filibuster!!"