Exactly. How can someone still say 'you're a cartoon character' after being with her for 12 years? The main character should come to the realization that Equestria is real. Otherwise, when Celestia and the others come for R.Dash, he might think he's having a dream or something. No, he realizes they're real, R.Dash is real and therefore, Equestria is real - not fictional characters even if MLP is a cartoon on Earth.