Closed balk thread

[Matthew F]

OBR 8.05 (b) The Set Position... From such Set Position he may deliver the ball to the batter, throw to a base or step backward off the pitcher's plate with his pivot foot... (c) At any time during the pitcher's preliminary movements and until his natural pitching motion commits him to the pitch, he may throw to any base provided he steps directly toward such base before making the throw. The pitcher shall step "ahead of the throw." A snap throw followed by the step directly toward the base is a balk.

If a pitcher disengages the rubber by stepping slow, high and exaggerated in one motion, why is that illegal and deceptive when a LHP can step slow, high and exaggerated (when attempting a pickoff at 1B) and that is not considered illegal and deceptive?

I understand the interpretation that the high step is not considered "backward". Why isn't the LHP high step interpreted the same way when the rules specifically say "toward"? Heck, the rule even uses an adverb (directly) for clarification when no such consideration is given to clarify the backward step to disengage the mound?!?

I'm trying to wrap my head around this, so any thoughtful responses are welcome.