Because it’s not mentioned in the Constitution. And the disposition of things not mentioned, is mentioned. Very specifically and very clearly.
Hardly. Chief Justice Marshall pointed out in McCulloch v. Maryland that implied powers existed: "Among the enumerated powers, we do not find that of establishing a bank or creating a corporation. But there is no phrase in the instrument which, like the articles of confederation, excludes incidental or implied powers; and which requires that everything granted shall be expressly and minutely described. Even the 10th amendment, which was framed for the purpose of quieting the excessive jealousies which had been excited, omits the word 'expressly,' and declares only, that the powers 'not delegated to the United States, nor prohibited to the states, are reserved to the states or to the people;' thus leaving the question, whether the particular power which may become the subject of contest, has been delegated to the one government, or prohibited to the other, to depend on a fair construction of the whole instrument."