Fed pitching question

[HugoTafurst]

In another thread, this is posted:

From March 2008 Plays and Clarifications on the ASA website.

PLAY: R1 on 1B and no count on B2. F1 commits an illegal pitch, by bringing the hands together a second time, which is called by the plate umpire, but continues the pitch. Just before releasing the ball R1 leaves the base before the release of the pitch. In (a) B1 does not swing at the pitch. In (b) B1 swings at the pitch and gets a base hit. In (c) R1 is on 1B and R2 is on 3B at the start of the play.

RULING: The illegal pitch happened when the pitcher brought their hands together, paused, the hands separated to begin the pitch, then the hands came back together prior to the release of the pitch. In (a) and (b) the ball became dead when R1 left 1B before the pitch was released. The fact that the batter did not swing in (a) or got a hit in (b) is irrelevant because the ball became dead when R1 left 1B early. Enforce both the leaving early and illegal pitch infractions, The Ball is dead and R1 is out and a ball is awarded to B2. In (c) The plate umpire should call illegal pitch when it occurs and then “dead ball” when R1 leaves 1B too soon. R1 is out, R2 is awarded home and B2 is awarded a ball in the count.

Rule 8, Section 7-S, Effect, Rule 6, Section 3-B, Effect-A Illegal Pitch
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I think I first became aware of this ruling 2 years ago and I don't quite understand the part about ruling the runner out for leaving early.
My thinking has been that there are many illegal pitches which can actually cause (if that is the correct word) the runner to leave early.

Don't runners time their leaving a base to the pitcher?
Isn't it reasonable to think that it is this illegal infraction could be the cqause of the runner leaving early?

Just wondering if I'm way off base on this one?

I know the case ruling, just seems funny to me.