there's a whole approach to literature for children in education that considers most fiction to be "windows." in this approach, it is crucial that children read a lot of stories, especially historic fiction, and that those books are about people, places, cultures, and ideas outside the child's experience.
the belief is that this practice will carry into adulthood and will also help a kid develop an understanding of the world that comprehends their personal life is not the "default." it helps develop empathy for those who don't look or act like them. it is incredibly important that a kid encounter many, many, many books where the protagonist does not represent them except in ways that foster the connection between the child's concept of self-identity and the idea that everywhere, always, people have been people.
it is helpful to read a story about someone whose life is vastly different from your own and then develop empathy via recognizing that they, too, are scared or shy or hopeful or hurt or lonely or growing. and it is additionally very important that those "relatable" details do not cause a mental rewriting of that character to be "just like me."
when you've had that reading experience enough times, it becomes even easier to read about people you don't find relatable at all. you now have the scaffolding to accept that someone who isn't like you at all and doesn't respond or feel the way you do is shaped by things in their own lives that are different than your own, or have lived similar experiences but had another reaction to them. and you can read a story and enjoy it or take something away from it without ever sympathizing with a character, or via finding compassion outside your personal understanding, because you have internalized some of the vastness of human experience.
all this to say that OP is entirely right. i love my blorbos that i find relatable. they can be an important processing lens for me. but if that is the only way you engage with fiction, especially if you find yourself reacting very personally and defensively to how other people talk about those characters as if they are attacking you, then give yourself the education you didn't get earlier: read books about people who aren't like you. read short stories and essays and historic fiction and modern day lit written by people from other places and times, representing themselves or their own experiences, and become comfortable with the sensation of looking through windows into lives that don't look like yours.
if you read a lot of fantasy or scifi, maybe you think this is already true. but look closer: are your blorbos acting in a way you would act? are the characters, regardless of setting, experiencing their world via the way they were written with a lens very much like your own? that's okay for fun! those books aren't necessarily BAD. but look for things where you don't understand or instinctively agree with how characters behave, where the cultural norms are fully accepted and lived by the characters, where the context is unfamiliar, and then spend time with that. let it stretch you. let it linger while you think about how you feel, and what it means, and how it impacts your perception of other people.
be curious! lean into wanting to know and learn!
