Defensive Intentional Drop

[tibear]

I have a quick question with regards to the "Intentional Dropped Ball" rule 6.05(l)

6.05
A batter is out when --
(l) An infielder intentionally drops a fair fly ball or line drive, with first, first and second, first and third, or first, second and third base occupied before two are out. The ball is dead and runner or runners shall return to their original base or bases;
APPROVED RULING: In this situation, the batter is not out if the infielder permits the ball to drop untouched to the ground, except when the Infield Fly rule applies.

Can someone please translate what the intention of this rule is???
The rule seems to imply that if the defense intentionally drops an easy fly ball with a runner on first. The batter should be called out and the runners returned to their bases. HOWEVER, the approved ruling then goes on to say that the only time this should be called is during an Infield Fly.

There is already an infield rule and if 6.05(l) is only called during an infield fly then why bother with 6.05(l). I'm obviously missing something.

Can someone make sense out of this???