Well, you can apply that same logic to every single other person in this world that is not you, so...
The point still is that a tupper should certainly feel like they're something more. Because this stuff is impossible to prove or test however, we don't know if they really are or aren't. I just prefer to treat potentially sapient creatures like they're actually sapient, as I feel like the worst thing is treating a sapient being like they're not. I don't think you'd like it if I treated you like you're not a real person - and well, honestly, the mind demon in my head feels more "real" than many other people in this world.
PS. the tulpas are still going to take over you and convert you into their slave, fodde-kun.
