The constitution delineates the limits of government power. It is a red herring to insist that a constitutional ammendment is not required, when a clear "government may not deny any persons right to bodily autonamy or sexual preference" would ideally stamp out any government interference in such matters.

You are right that all rights are retained by the people, but what has people mad / worried is the states legislating against the will of the majority (specifically because there is nothing stopping them from doing so at a federal or constitutional level).