It is added to be a silly/random thing, but it's not to make fun of gay people.
In the previous season (season 5), it’s mentioned in an episode that Lisa got the family to march in a LGBTQ rights parade. In the same season as this meme (season 6), Patty, Selma, and Marge ask the movie critic, Sherman, in a fun gossipy way, which celebrities are gay.
The Simpsons is pretty pro-LGBTQ overall.