Because not everyone agrees with this interpretation of things?you have your rights from your humanity, and your rights are vast, the founders knew this, some wanted a bill of rights, some didn't, the ones that didn't thought by listing rights, it would in essence limits rights to only what is on the listing in the constitution, which are a few, however the 9th amendment was added to state that citizen's have more rights then are listed in the bill of rights, and placed on the federal government restrictions, that the federal government will make no laws which infringe on the rights of citizens.
since the days of the founders, people have had their vast rights infringed on by government which are not listed, and the USSC, has recognized those rights which are not listed, like the right to privacy, right to association, and placed further restrictions on the government which they are not to infringe on.
so the constitution never gave you a right, it just recognizes rights you have from your humanity, and restricts the federal government from passing any law which would again...infringe on them.
so rights of the people cannot be repealed, because their are no rights in the constitution, just a prohibition on government.
so how can government repeal a restriction........... which is placed on them.
it would be like a robber, having the ability to change the law, to make is crime lawful.