Having LGBTQIA characters in cartoons and in other forms of entertainment is catering to them.
By showing people they exist? They have been LGBT characters in entertainment for centuries, like the stories of Greek mythology and books from the 18th and 19th century such as Fanny Hill and The Picture of Dorian Gray.
Not to mention there have been LGBT writers and artists for centuries, like Leonardo Da Vinci and Emily Dickinson.
The Goofy Gophers from The Looney Tunes Show from 2011 were an openly gay couple.
I cannot find a legitimate source (like the producers' Twitter account) that confirms this is true. All I got is a Wikipedia paragraph without any citations.
Some of the characters in Steven Universe were openly gay.
Again, nothing blatant was shown on the show for the most of its run. The show waited until Season 3 to deal with Pearl's lost love arc, and nothing was really shown. And they waited until Season 5 for Sapphire and Ruby's wedding, which got immediately pushed to the side to deal with the series villains.
They have same-sex couples in Clarence.
Only Jeff's moms, and they were never shown to express any romantic gestures to each other, unlike Clarence's mom and her boyfriend in the show.