Intent is subjective, and can be demagogued by on-air personalities with a "punish mean ol' Alabama in the guise of injury prevention" agenda.
While the definition of defenseless is left vague in the NCAA rulebook, the examples given make it clear the kind of situations that they are intending to protect players in.
Code:
a. A player in the act of or just after throwing a pass.
b. A receiver whose focus is on catching a pass.
c. A kicker in the act of or just after kicking a ball.
d. A kick returner whose focus is on catching or recovering a kick in the air.
e. A player on the ground at the end of a play.
f. A player obviously out of the play.
Interpretation of this rule to include players like Murray leads to logically absurd conclusions, and enforcement of such is unprecedented. Which means Alabama will probably get screwed.