While there are a wide variety of stories, we still fall into the habit of telling and hearing one story and they're often stereotypes of groups of people. From religion, race, sexuality, gender, and cultures, we tend to be limited to the one or few stories we hear about groups of people, especially minorities. This is also why good representation in media is important and having more variety of stories in mainstream media helps dispel stereotypes and misinformation and lets people see themselves in the media we consume
For example, Asian characters in media might often be stereotyped as smart and good at math, and while I may fit into that stereotype, there's more to me than just that. I'm very much artistic and don't particularly like math all that much. Plus, this bias may put pressure on other Asian people to fit in and feel shame when they don't meet this assumption.
Queer characters are often very flat or only focused on when it relates to their queerness, and stereotypes like gay men being feminine or more harmful ones like trans character, especially trans women, being aggressive are still shown. The other thing that media will do is queerbaiting by not explicitly saying that a character is queer to appear progressive or have throwaway lines that can easily be cut out for distribution in other countries that aren't accepting. Disney is an example of this with all of their "first" queer characters barely being in the movie.