Dom sayeth:
(in my opinion and from my perspective of course, though I would tend to think this should go without saying).
Depends on the statement. If I say this thread isn’t about the Oscars…that’s kind of accurate but mostly not true. If I say this thread isn’t about Syria, that’s definitely accurate. Whether something “is about” something sounds like a factual statement.
Nothing is factual when it comes to art, especially when you’re talking about what something “is about.”
It is possible to be mistaken. Not all is so relative. In any event, whether art is about X doesn’t mean an objection to element Y is not well founded.