It’s not really prejudice, it’s more accepting what is the established rules and trajectory of the story and that the parallels that came before it are part of this. If they gave Rey her own sense of self and own motivations then it could’ve worked much better I think. As it stands now they gave her parallels because of nostalgia and nothing more. I would’ve been accepting of Rey Skywalker if she remained Random because the argument of her being a “No One” could be paired with the idea she found identity in the generation of Skywalkers before her and their shared experiences as she too had humble origins. Despite how meta it is I find it kind of works since it didn’t tip over to mixing up with established characters but her own character who happens to parallel the family who came before her.
It sounds like prejudice to say that “a Palpatine can rise above their background and become a hero.” Rejecting one’s heritage to adopt something new is a welcome addition rather than relying on pre-destination as the only determinant of one’s worth. Sometimes it’s worth it to break the rules for something more compelling. I’d have preferred “Rey nobody,” but “Rey Palpatine” represents one’s rejection of negative heritage. Breaking the cycle of abuse and horror in one’s family is a positive piece of symbolism, a welcome addition to the canon. As somebody who knows people that have had difficulty with their families, the theme of ascending above an awful family resonated with me.
It’s about respecting all of Star Wars and not just picking and choosing the pieces of the story that best suit the storyteller. It’s about accepting the creator (George) had a story and following the rules he created for his universe.
That’s literally been the state of the franchise since the '90s. Picking and choosing is an important part of enjoying any franchise, even within official media (see the state of any fandom today).
But let’s say we have to limit ourselves to the existing rules of “George’s universe.” The idea of ascending above one’s heritage is Luke avoiding the fate of his father, just like Rey escaped the legacy of the Palpatines to join the family of her mentors. It fits. Not great, but it fits the “rules for George’s universe.”