I need a rule interpretation for strikes.

[Coach Al]

I need a rule interpretation. I use to ump until my arthritis go too bad and I had to quit. As I was taught in several umpire clinics, if a pitched ball strikes the plate it is a ball, unless the batter swings at it. Am I correct or was I taught wrong? The rule reads Section 5. A BALL IS CALLED BY THE UMPIRE.
A. (Fast Pitch) For each legally pitched ball that does not enter the strike zone,
touches the ground before reaching home plate, or touches home plate, and
the batter does not swing.
EFFECT: The ball is live and runners are entitled to advance with liability to
be put out.