Ruin Explorer
Legend
It wasn't "designed" at all - this isn't a scientific term.The good basis for insisting they're correct is their memory, faulty as it might be. Gaslighting is done deliberately for the purpose of manipulation by behaving in a deceitful, dismissive fashion, so when you say someone is gaslighting another person you're saying they're the bad guy. Disagreement with someone does not a gaslighter make. But I guess this is just a good example of how a term originating in a specific context has been introduced to the wider world and subsequently applied to situations it wasn't designed to be applied to.
And I think the line is far, far blurrier than you actually admit here.
The reality is, especially for some people, especially from certain older generations, memory can become a competition, not a collaboration. Either their memory is right, or its wrong and they are somehow shamed/dishonoured (and self-concerns about their own potential infirmity factor in too, even when it's something that could happen to anyone with even a couple of decades of memories). So people can be far more insistent and pushy about their memories being "correct" than is actually merited by the memories (and indeed, can be demonstrably wrong, usually due to fixed points in time as discussed earlier), for emotional reasons rather than what I would call "real" certainty. And is that strays pretty quickly into the territory of gaslighting, and often in fact presents in exactly the way you describe - as manipulative and dismissive. Complicating matters further is that some people want to shut down (accurate) memories of bad behaviour for various reasons.
Deceitfulness is something harder to track and rarely possible to be truly certain of outside of the fiction or very unusual admissions.