The correct answer to this open question is the following.
In the process of creation, I think artists should follow a set of ethics because although the expression of art is subjective, it should respect the moral, religious, and belief systems of other people.
I know this is a complex and controversial subject because art is supposed to be a free expression of any topic, at the end, artists should be cautious of not offending "core" belief systems or critical issues that exist in society. Otherwise, people will be offended and can act against the artist or artistic expression.
So in conclusion, artists should follow a code of ethics. They can express criticism on any specific subject but that does not mean that they have to be rude or offend other people's ideas, culture, customs, or traditions.