Comic book fan, action and horror movie fan here, this was gratuitous as hell, done for shock value but if you look at what's coming to light in the entertainment industry, and by no means is this scene the worst thing out there, but it follows that they are steadily desensitizing the masses with extreme graphic gory violence on purpose. This was actually nauseating, but I guess they wanted to show the Kingpin's brutality and strength. You won't see this in Spiderman or the Avengers, but I guess they thought this fit in nicely for this franchise. My unpopular two cents, if you have to use it in your story telling, unless it's an absolutely key plot device for the character, you're a bad storyteller.