That said, I'm sure the death count numbers from the Rasht Massacre are staggeringly higher than the initial tallies of 2-5k.
My daughter’s hair stylist is Iranian (she was an accountant in old country). When Jimmy Carter’s wife died, she said “I’m happy she’s dead.” I’ve never seen anyone else say a negative thing about the Carters personally. Even die hard Republicans who think he was a weak President don’t hate him as a person. But this is not an uncommon sentiment among the Iranian diaspora.
In any case I was simply responding to OP's "why" question and that their theory on blaming Reagan allegedly vs Carter on a narrow point, highlighting that particular case is temporally much later, and has no relevance to the underlying reason Carter is hated over there.