The comic may be a joke, but I feel like this is an issue in diversity.
Take an author who has three characters. They want better representation, so one white character becomes black.
But, it turns out that character gives a third-act betrayal. Now it’s playing up the theme that black people are deceptive and untrustworthy.
Or, they try making the second character a woman. In a key conflict, that character pulls a very stupid move that lets the bad guys get away and results in an exciting chase scene. Now it evokes the idea that women are stupid and ill-suited to detective/enforcement work.
I really want a world where we can safely set up characters for moments of failure, evil, etc, without large crowds either feeling offended, feigning offense, or worse, taking it as validation of their bigotry.