Morality, humans rights, and all that the topic encompasses, has always been fluid. What we call human rights today is vastly different from notions that just a couple of generations ago where believed to be common sense.

I do not think morality is fluid and regardless of what people might have once believed to be 'common sense', there are things that have always been morally wrong and will always be wrong and at no time in the past or future could ever be right. Slavery is one example, murder another.

Am I misunderstanding what you are saying?