There is no such thing as liberty in general; there are only specific liberties. Fine-sounding principles like “The greatest possible liberty compatible with equal liberty for others” settle nothing, because there is more than one possible arrangement of equal so-called liberties. So one must bite the bullet and decide which liberties are real liberties in the sense of belonging to our true good. Every claim of liberty P entails denial of liberty Q.
If the slaveholder has a right to own slaves, then his slaves have no right to be free; if they have a right to be free; then he has no right to own slaves.
If a mother has a right to an abortion, then her baby has no right to live; if her baby has a right to live, then his mother has no right to an abortion.
If the registrar of marriages has a right to uphold natural law, then two persons in an unnatural association do not have a right to be called married; if they have the right to be called married, then he does not have to right to uphold natural law.
So those who try to protect themselves by appealing to liberty without appealing to natural law will find their appeal to liberty empty. It is terribly easy to establish tyranny (by the standards of natural law) in the very name of liberty (by the standards of revolt against natural law). And that is how it is happening.