Example given, if there is a TV show and there is this character, who is the only gay character in the show, and he is a villain.
Some years ago, I had heard someone complain about "This character is the only ___ character in the story, and they decided to make this character the bad guy?"
And back then, I wondered if that meant that the villain shouldn't be LGBT+, POC, disabled etc... Or that if you had a villain character who is ___, then you should also have a ___ character who is a good person.
An example of the latter one would be the gay villain who wants to blow up the entire planet Earth, and then there being this other gay character, who wants the world to be a better place and treats most people with kindness.
But those things perhaps depend on whether this character is a villain because of them being ___ or if they are a villain who just happens to be ___.
And also, if that character is stereotypical, e.g. if the bisexual main antagonist is a cheater (because of that one stereotype associated with bisexuals)
Okay, I kinda understand why some people don't like that, because it makes all people who are ___ seem bad or makes it seem like the creator of the media doesn't like those people.