Right, so it makes no sense anywhere else.

Defining something as “art” or “not art” seems a rather simplistic worldview.

Does art need to be “appreciated by anyone” to be “art”, is art only what is popular, or simplistic enough to be understood by a mass audience?

Is stencilling over/tagging a banksy vandalism, or is it a making a statement on the middle class hypocrisy of its widespread acceptance of street works from one author and the derision of others?

Which of these are “art” or “not art”…

• banksy later tagging his own work
• banksy later tagging his own work but not claiming authorship
• banksy later tagging his own work, but publicly saying someone else did it, and that he doesn’t approve
• someone else tagging banksy’s work, and banksy publicly saying that he approves
• banksy stencilling over the mona lisa (on the actual paint)
• banksy stencilling on the outside wall of fallingwater
• banksy stencilling something regarded as offensive by some people
• banksy stencilling something you like on the front of your house
• banksy stencilling something you don’t like on the front of your house, but is widely liked by others
• somebody else stencilling the same thing on the front of your house

Seems like the rules for what is/isn’t art could be quite complicated. There would be endless possible scenarios to judicate on. Not to mention, who gets to decide? Popular vote, experts, the owner of the substrate?

Much simpler to let art be undefined and interpretable however one wishes.