Ideas have consequences. And bad ideas have bad consequences. One bad idea is that of moral relativism: the idea that there are no objective moral absolutes, and morality is ultimately a matter of personal preference. If there are no objective moral standards which we all can appeal to, then those with the most power end up being the ones who are the most “right”.
The weakest and most powerless end up being the ones who are “wrong”. Thus might makes right, and we have seen this far too often in history.