Are ethics a necessary element of art?

Arthur Koestler “insists that an object’s status as original or forged is extraneous information, incidental to its intrinsic aesthetic properties” (Alex Neil and Aaron Ridley, 2008. Arguing About Art. Routledge. p. 103). After reading Alfred Lessing and Denis Dutton’s views on Fakes and Forgeries, it appears to me that originality and morality are not necessary ingredients for either the creation or appreciation of “great works of art” from an aesthetic consideration. The object d’art being considered is neither a moral agent nor a moral patient.
We know it is possible to regard highly works of art without knowledge of their origins or the purpose behind their creators’ manifestations of them. As discussed in class, the history and authorship of works of art as “authentic” may be inaccurate, either through ignorance or deliberate misrepresentation. The judgment of authenticity is relative to the author of the work not the work itself, and therefore should be considered separately from an aesthetic review of the work.

My question is:
Are ethics a necessary element of art?