Because not everyone submitted for them, their averages would be way higher then every Pokemon or way lower.
Don't worry the 11 you took from Giratina doesn't affect its place, even with it, it still stays at the same place. 11's aren't that impactful as something like a 0 or 1.
nobody thought it was necessary to sabotage that, it seems
the only good thing it did was make Porygon 2 viable 
