There's always been a streak of outrageousness in animation. It goes back at least as far as the 1920's, when N.Y. animators from different studios collaborated on a porno cartoon called Buried Treasure that screened at a testimonial dinner for Winsor McCay. In the early talkie period, before the Hays Code clamped down, there was no shortage of sex gags, ethnic gags and gay gags in cartoons.
Once the Hays Code kicked in around 1934, all Hollywood movies including cartoons got tamer. Sex was particularly taboo. While there were performers with gay personas like Franklin Pangborn, their gayness was portrayed as fussiness and affectation. It was out of the question that they could interact with other men on a romantic or sexual basis.
Under the Hays Code, animated lust turned into exhuberance. Avery's wolf is the best example of this. The gags were built on visual variations of arousal, but consummation was out of the question. It's doubtful that Avery could have gotten away with even this except that there was a war on and the Hays office loosened up for the sake of national morale.
After the war, things got even tamer than before. Racial caricatures pretty much disappeared except for Speedy Gonzales. Bugs Bunny cross dressed, but that was done to showcase his antagonist's stupidity or neediness. Avery moved from sex to other topics.
The Disney studio's position was probably tamer than most. While there were some sexy girls in Disney films in the 1940's (Sluefoot Sue in Pecos Bill; the girl in Duck Pimples; Donald chasing live girls in The Three Caballeros), by the '50's it was back to classic stories and talking animals.
So where did Plutopia come from? And how did it escape without anybody seeming to notice? If you're not familiar with this cartoon (and I hate to spoil it for you), in Pluto's dream the cat is portrayed as a gay masochist who gets off when Pluto bites his tail. Pluto is happy to oblige as he's rewarded with bones (the phallic imagery is inescapable). Pluto and the cat are both receiving the oral gratification they crave.
Was the Hays office asleep at the switch? They never would have let a live actor portray masochism in anything other than a film set in an asylum. Did Walt Disney understand what this cartoon was really about? And where did the idea come from? It's completely atypical in Charles Nichols' directing career. It doesn't appear that there was anybody new on the crew who might be responsible.
Was it the result of somebody's repressed life surfacing or did somebody decide to see how much they could get away with? How much did Jim Backus, the voice of the cat, add to the characterization? And was the crew laughing hysterically while they made this cartoon or did they just not get it?
What about animation fans? While they search out pre-code cartoons from Fleischer, Iwerks, Harman-Ising and Van Beuren for their outrageousness, pine for the WB censored 11, and dream of John K. cartoons created without censorship, do they realize what's in Plutopia and that it's available in a pristine copy?
Maybe it's because nobody pays attention to Pluto. That's the only answer I can offer for how this cartoon got out in the first place and for how little attention it gets. But I sure wish I knew who dreamed this one up and how they got it into production.