Things are irrational until we understand the dynamics behind them. Then they become rational. When she decided not to press the issue, that wasn't a rational decision made on logic, it was an emotional one where she prioritized one kind of truth, that it was
her hurting her child, over another kind of truth, that it was the hand licking that was hurting her child.
Only in retrospect did the actuality of the situation make itself known. There was no logical way to weigh one alternative against another. Sure, one later manifested, but it didn't exist in the moment.
This is why I say she used irrational means to decide to lay off. I recognized maternal instincts in her reasoning, which I'll quote here:
> Finally, I had this moment where I felt that my efforts to ramp up the pressure to force him to stop had crossed some line. I felt I was turning into an abusive parent.
> At that moment, I decided this had to stop. I didn't care if he licked his hands the rest of his life. It couldn't be worse than this.
Rational analysis failed, some other way of deciding how to handle it took hold. Notice the semantic shift here. She moved from articulating her decision-making process in a cold, logical fashion, then after the failure, she shifts to an empathic, emotional basis.
Over-reliance on and unexamined belief in rationality drives this. Sometimes there are multiple truths out there that you are going to have to choose between, with nothing to help to distinguish them. The over-rational mindset will concoct meaningless and even counter-productive forms of "rationality" to paper over their fundamental ignorance. The colloquial term at hand is lamp posting.