It's even beyond being a freebie seeker. It's the notion that the world owes them something, and everyone needs to jump through hoops to provide exactly what this person wants. Even worse, the demands are frequently lacking in grammar, punctuation, or even any notion of sense. It made me quite happy to have dabbled in obscure and unpopular fandoms.
I always want to hug authors who tell such reviewers that sorry, it's their story, they will write it their way, and the reviewer is welcome to write the story the reviewer wants to read. (And then, if they're like me, they go and wonder if they were over the top saying that. )
We all love a review, though. Even those quick, "I loved it!" reviews can keep us going.