Why is a foul worth 3 points...

[bellnier]

Jump shooter inside the arc makes his attempt, misses, and is fouled while he is still in the air. He is awarded 2 FTs.

Same jump shooter is outside the arc, makes his attempt and misses, and is fouled while still in the air. He is awarded 3 FTs.

Why the difference? I assume the FTs are awarded because a player must be protected while in the air, but is the player more vulnerable by 1 FT just because he's behind the arc?

I realize this isn't a rules question per se, but so many of you know the philosophy of certain rules.

Thanks...