Interesting. "Thin skin". Why?
It's not his work anymore. Though I recognize the vast difference in scale, you can't ask the architect to take done Empire State Building simply because it's not used for zeppelins as originally intended.He should take his bull back or deal with the fact that he doesn't like one spin on his work.
This is not the case. 1) It is his work. He still possesses title to the work, as well as licensing rights. It is on indeterminate loan to the city of New York. 2) It's entirely movable. It was moved to its original location, then it was removed, then it was moved to its current location. It weighs 7000 lbs - less than a lorry.
Licensing, rights - sure. His possession, for him to rule over however he wants. It has, however, also become a symbol, whether the owner recognizes it or not. It's a symbol for NYC and a symbol for Wall Street. If he takes the bull out, he'll take away a bit of culture - of the city, of the nation and of the world. I doubt there's a replacement he can do that will have as much weight, culturally.