[Eisenstein]

I think the intent of the original comment 'they lied about doing no evil and we should dislike them for it and feel betrayed' is key here. Yes, technically 'lied' is not the correct term, but nitpicking it by using a completely different scenario (a child making a grandiose decision motivated by the nature of childhood) is going from 'wrong term' to 'fundamentally misunderstanding the nature of trust'. I think a better example than any of the ones brought forward would be a loan. Would you trust a child to pay back a loan or to be able to conceptualize the requirements of what it means to commit to doing so? If not why would that be a useful example of honesty in this context? Sure, the child would not be dishonest about the payment, but you wouldn't trust them with it.

The parent comment was making a statement about dishonesty in the sense that when an adult makes a commitment, we hold them to that unless we do not trust them, and those were people we thought we could trust. They have gone back on that and now we think they are deceitful because they betrayed our trust. Whether or not they believed it at the time they said it still makes them scumbugs for having changed their mind at a later date.

[cgriswald]

This is not a technicality or a nitpick. The scenario offered was different in order to make it easier to see the error, not to suggest both scenarios are somehow identical in every regard. Your doctor scenario also demonstrates the difference.

Regardless, suppose you did lend that child money and they didn't pay you back. Then suppose as young adults, they come back to you and ask to borrow money again. If they always intended to pay you back and have now matured (and maybe even ultimately did pay you back years late), you'd be far more likely to lend them money again than if you found out somehow that he never intended to pay you back the first time.

There is meaningful difference between "This person committed to something and ultimately didn't live up to that commitment," (or only lived up to it for a certain amount of time, etc.) and "This person lied when they said they were committing to something because ultimately they failed." In one case they changed their mind and perhaps knowingly went back on their word or were unable to live up to their word due to forces outside their control. In the second case abuse of trust was the entire plan. Both of these say different things about the person who violated our trust and whether and with what we can trust them in the future.