Bringing Charles Darwin into the conversation does not help your point.
"Is it worse to have some condition of your birth used as a casual insult -- a reminder of your misfortune? Or is it worse to be constantly patronized, often behind your back by throngs offended on your behalf?"
This is a false trade-off. The whole conversation started because someone used a harmful word, knowing full well it was harmful. If they refrained from using the offensive word they knew was offensive neither condition would have happened (casual insult or patronization).