>>33701661Pokemon are physical beings. When they're stored on a computer we can only assume that their data references their physical attributes and rebuilds them when the process is reversed.
The material of a Charmeleon's skin or the size of a Garbador are all stored and then reversed as the Pokemon goes from data to physical form.
Porygon has none of this, it doesn't have skin or size or any physical attributes - you wouldn't be able to rebuild it the other side.
If you're making the assumption that the attributes would be pre-programmed, then you could potentially catch a Wailord and then change it's size variables to make it less than an inch wide. It'd be a game-breaking mechanic in the Pokemon world.
You could make an Onix wider than it is long, or a giant Ditto the size of a planet and kill everyone when you get it out of its ball - Villainous teams would have used this as a strategy instead of catching legendary Pokemon.
Therefore Porygon can't do this, otherwise you could just develop a Porygon big enough to take over the world. Porygon makes no sense.