Infield Fly Rule Edit Meaning

1.

If there are runners on first and second(Or the bases are loaded) and less then two outs when the batter hits a pop-up to the infield, he is automatically ruled out to prevent fielders from dropping the ball on purpose to try to turn a double play.

Since the bases were loaded with no one out, that easy pop-up became an infield fly, so the third baseman doesn't need to catch it.

2.

Somebody explain this