People are allowed to like names from their own culture and other cultures and, shockingly, are allowed to use them! People are also allowed to dislike names from their own culture and other cultures. There are no rules about having an opinion on a name.
In my opinion, since this is the original intent of the topic, I would classify Sir as a typical "celebrity" name (in the league of Reign, Saint, Pilot Inspektor etc.), whether or not the celebrity who used it was black, white or purple, has no weight in my opinion. Sir is just going to cause confusion in general greetings/address/conversation down the road, and on that basis, and that basis only, my opinion is that I dislike it.