under 1.2 exposing one's king to attack is not allowed.
This is your "point", so think about it. If Kxf8, what is your move doing for Black?
The answer goes back to your point, it is exposing the King to an attack. So basically, you defeated your own arguement with your own answer.
You're over-thinking the analogy of the king and his army. The pinned piece exerts its influence over the board from where it stands. It is a long-range piece. Black cannot take the queen because that would place it in check. A child can understand that!