In my opinion the “Mary Sue” stuff is absolute bullshit that has now seeped into the movies itself. The urge to pacify crying fans is the reason we’re now left with the fan wanking trash that is Rey Palpatine.
Though I suppose the only casualty is the integrity of Rey’s character, and who cares about that when you finally have an explanation for how “OP” she is! The saga is saved!
I don’t think you should blame it on the fans. None of the fans who hated Rey Nobody like Rey Palpatine. They see it for what it is: a misguided attempt to please everyone that resulted in the sequel trilogy having no clear direction.