Because the rights of the constitution is only by bill.
Individual rights were included in the Constitution because the writers of the Constitution wanted to protect the individual from their government and enshrine certain liberties and rights to make this process well defined. Following colonialism and the intrusion of the British Crown into many aspects of an individuals life the writers of the Constitution sought to prevent this from occurring in the soon to be formed Government of the United States. Enshrining individual rights was an essential goal of the Constitution.
Individual rights were included in the Constitution due to demands from Anti-Federalists during the ratification debates. They sought protections against potential government overreach, leading to the promise of a Bill of Rights. The first ten amendments, which guarantee essential freedoms, were ratified in 1791.
;