That line of reasoning gets applied to literally every single piece of fantasy media and it's so annoying.
"Oh, Finn is just a boy in a coma, imagining all the fun Adventure Times"
"Harry Potter is a kid who got into a cult of the occult to get away from his abusive family, and got brainwashed by the escapism."
" My Little Pony is just a hallucination of a real horse that accidentally ate some shrooms and now she thinks she's Pinkie Pie."
"I bet that Lord of the Rings is just a dream cooked up by some short peasant dude who got drafted for the Crusades and went mad."
"Gravity Falls is made up because the kids couldn't handle being so bored in such a rural backwoods village"