They are two main ethical therories under which issues of censorship and free expression can be evaluated, these are consequentialist and deontological theories.
Consequentialism, as its name suggests, is the view that normative properties can depend only on consequences. This attempts to posibly justify the censoring of art, for the better good and the possible reactions that may stem from viewing of such "unethical" art that choses a different view from that which is the social norm.
While on the opposite side of the spectrum you have deontology which disucess choices that are morally required, forbidden, or permitted and the assessing of whether certain situations are
under those categorical branches, for example is the art work in question morally forbidden?
Art Censorship:
A Dialogue into the Battle between Us and Them
“There are worse crimes than burning books. One of them is not reading them.”
- Ray Bradbury