Almost everyone watches TV, plays video games, reads books or does some combination thereof. All these options are great forms of entertainment and a great way to relax. Everyone loves them, but not everyone is represented in them, at least not fairly.
Most of the characters in any form of entertainment media fit into a well-defined set of basic characteristics. That is to say, the vast majority of them are white, straight, cisgender, able-bodied, and male. This is not to say there is anything wrong with having characters like this. It’s perfectly fine, but the issue is that in today’s media, there is not much variety. There are very few characters that are African American, Latino, Asian, homosexual, bisexual, transgender, disabled, female, Muslim, Jewish or any combination thereof. There are very few characters with these traits, especially compared to the number of them that are white, straight, cisgender, able-bodied, and male. And when there are minorities present, it is usually only one token minority character, such as an African American in a group with five white people, for example.
This is not to say there should be less white characters or straight characters and so on, just that there should be more characters that are minorities. There should be more African-American female characters, more transgender characters who are gay, more bisexual and disabled Latinos characters, more asexual Muslim characters, more of any and all of them because these types of people exist and they deserve to be seen and heard. People want to see characters that they can connect with and feel good about. They want to see that an African-American woman can be a superhero so they can believe they can be a superhero, just like a white man can with Captain America. (Or almost any other superhero. Think about it, how many of them are white and male?) People want to watch sitcoms and dramas with diverse casts because the audiences are diverse. The simple fact of the matter is that representation matters.