I don't think you're following my line of reason. You and I believe that red point is a planet because someone else taught us that. We don't have any independent evidence -- we simply believe what others have told us. I'm not arguing about the definition of a planet, or what 'Mars' is -- I'm arguing about what you and I _KNOW_. We don't KNOW that red point is planet -- we've simply been taught, and believe it. For the record, I believe Mars is a planet, despite having no personal experience or evidence whatsoever.
People have been 'seeing Mars' since way before we actually knew what it was.