I have heard and read from kiruv books, outreach speakers, pamphlets etc. that Orthodox Judaism doesn't like "Moral Relativism" (the position that moral or ethical propositions do not reflect objective and/or universal moral truths, but instead make claims relative to social, cultural, historical or personal circumstances)
In my understanding, however, Judiasm DOES believe in Moral Relativism: Miriam got instant tzaarat and Moses was banned for life from Eretz Yisroel because their sins were magnified because they were at such high levels. (Also, Reuben didn't really sleep with his father's wife, rather his action should be considered to be so heinous because he was such a big tzaddik)
Why does Judaism seemingly object to Moral Relativism yet seemingly hold by it?