We’re being somewhat pedantic now. Call it part of culture. Its the same as calling it a tool. Yes, it is that. But this particular aspect of the culture went on to become the basis of a massive establishment changed the course of history as stated above.
Not to mention divine right is far more than just an acceptance of custom. Its an undebatable justification. Religion is truly like nothing else in the world, and you keep trying to pass it off as some philosophy that is there one day then gone another.