Right, so that's a conveniently pragmatic approach to the issue.
Most of us nerds are fighting the idea of diamonds signifying social standing. The practice, and culture of giving expensive rings is objectively wacky. You're right that in your social circle taking an odd position will cost you your reputation, but consider that in the past many morally reprehensible practices were the norm and being an odd one out would cost you your reputation. If you operate on a framework so rigidly tied to social standing you might make pretty wacky decisions down the line. Ultimately, decisions made on this framework may not always be the wisest decisions.
Most of us nerds are fighting the idea of diamonds signifying social standing. The practice, and culture of giving expensive rings is objectively wacky. You're right that in your social circle taking an odd position will cost you your reputation, but consider that in the past many morally reprehensible practices were the norm and being an odd one out would cost you your reputation. If you operate on a framework so rigidly tied to social standing you might make pretty wacky decisions down the line. Ultimately, decisions made on this framework may not always be the wisest decisions.