This is a semantic distortion of what most people mean when they say something is political.

Yes, a painting of fruit can be discussed within a political context.

But when we say a piece of art is political, we don't mean it can be seen within a political context. We mean that the piece of art is intended to be seen within a political context, or that the political context is blatantly apparent. Yes, this means whether or not something is political is subjective. That's how people use the word, just as they might describe something as angry or meaningful.

When people say "everything is political", just as they say "racism is prejudice plus power", they are discarding the in-practice meaning of these words and replacing them with meanings that were invented to support a particular cause.