Off the top of my head, SpongeBob SquarePants, Danny Phantom, Fairly Oddparents, The Big Bang Theory and It's Always Sunny in Philadelphia all have jokes, if not the main plot point of the episode, that are just mocking the existence of LGBTQ people.
Danny Phantom noooo
I am referring to the episode where Danny and Tucker are sleeping next to each other and they end up rolling onto each other, so Sam takes a picture for blackmail material.
It was probably the least bad example of what I listed, but it would definitely not fly today.