Even the glans loses sensitivity. On an uncircumcised penis, that whole area is basically a mucus membrane. On a circumcised penis, it becomes dry an rougher, like the skin on your knuckle. It absolutely does reduce sensitivity.

Also,

I would consider that as much loss of sensitivity as amputating a leg is loss of sensitivity.

You wouldn’t say doctors should amputate babies’ legs to reduce risk of gangrene, would you? How is that even an argument? “Oh, those nerve endings don’t matter cause it’s just like losing a leg, nbd.” What the fuck?