TV
Sometimes the only way you can feel good about yourself is by making someone else look bad. And I'm tired of making other people feel good about themselves.
— Homer · The Simpsons

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker first describes feeling better by making someone else look bad, then complains about giving others that benefit. The second sentence turns the thought back on the speaker, implying that their own shortcomings help other people feel superior. That reversal supplies the joke.
Context reviewed