The problem is that the line of being “real” or not is defined in the eyes of the beholder. Is a computer a real computer if it lets me rm -rf / or is that just stupid system design? Is a computer not a real computer if you can’t move the menu bar or taskbar or are the designers of the computer allowed to have a strong opinions on such topics? Everyone will draw those lines in different places.
We could use this same philosophy to claim that a laptop isn’t a real computer because it doesn’t let me add expansion cards, doesn’t have GPIO pins, etc. All those lines in the sand are in the eye of the beholder.
In your eyes, a computer that doesn’t let you write and execute arbitrary code on the device is not a real computer, but to the vast majority of people on this planet have no ability or desire to write code ever on any device, so for them that distinction is completely irrelevant. That would be like if my garbage man told me that my Toyota Tundra isn’t a real truck because it can’t compact garbage.
But you could always make an app to handle car rentals for ipad or iphone or whatever. You could make an app for lawyers doing documents. That was never the argument against "ipad isn't a computer." It doesn't expose the file system to you. More than anything, it tries to keep up the curtain between you, Dorothy, and the wizard, who is just a man after all. That is why it is not a real computer and will never be one fundamentally.