But that isn't what Marx meant by that phrase.Marx was right. Karl, not Groucho,
Religion is, in fact, the "opiate of the masses."
The sole purpose of religion from a sociological point of view is to keep the "poor and huddled masses" from rioting by promising it will all be better in the next life.
This isn't a critique of the "Golden Rule" but of the methods used by religion to control its followers and ensure those who "deserve" power stay in power.
Does anyone need "religion" to know that hurting people is wrong, stealing is wrong, murder, rape, are wrong?
OH, actually, many religions blame women for the unleashing of evil upon the world, Eve, Pandora, Angrboda, these gave religions permission to control women and thus keep their evil at bay.