As Federalists we believe that a Bill of Rights is unnecessary because the Constitution does not give the Federal Government any powers to infringe or interfere with individual rights and there is no need to protect an individual from a government born out of the fight for freedom.
Firstly, the Bill of Rights is already included in the constitution. The Constitutional Convention did include specific protections in the Constitution. Articles VI restricts government interference with religion and speech. It also provides certain protections in criminal law. It guarantees a protection against illegal imprisonment except in times of rebellion or invasion. It also prohibits imposing punishment on a person's descendants. It forbids any state to pass laws impairing the obligation of contracts. Thus, it would be considered a waste of paper to establish something that is not needed at this point in time. Also, each state has its own declaration of rights that is considered as sufficient protection for the people.
Also more relevant is the belief that every man has certain natural inalienable rights that need not be enumerated.
Secondly, this new government is different from every other type ever created. In this Federal Government powers will be given to the persons that you elect with limitations. Whereas in a Royal government powers are given primarily to the King, who could intervene with individual rights. This government is one who believes in liberty and justice for all and must be able to be trusted by all citizens. But, the Royal Government is one that simply rules for the happiness of himself.
Also by specifying certain rights for protection might that other rights could be tampered with. Also such protections would be insufficient on those occasions when control is most needed.
Many people argue the fact that even Federalists like John Adams and Thomas Jefferson agreed that a Bill of Rights should be included in the Constitution. But, this argument fails to realize that under the pressure of Anti Federalists some Federalists are forced into the act of negotiating. One of the most important point is that since the powers delegated to the new government does not include authority over individual rights.