Maybe I'm alone on this, but my family used to put dead birds, squirrels,... found on our terrain in the trash... I really got furious and said that those were living beings and they deserve proper burial even if it's some random animal found in the backyard...
The only way to make them understand what It means was to say: "Don't worry, I will also put your dead body in a trash bin".
That's fine, put me in the trash. Reverence for dead bodies is weird. They aren't living, they will never be living again, they are empty husks of meat. The only reason to bury them or do anything else with them is to avoid the spreading of rot and disease. Putting them in the trash is just as acceptable as throwing out that 2 month old cooked beef you forgot about in the back of the fridge.
It's older than the Simpsons for sure. Flushing your (mostly/presumed) dead pets down the toilet was how the urban legends of alligators in the NYC sewers came about...
Kinda in the same vein: I was taking an emergency dump at a Walmart. There was a person in the stall next to me taking a dump as well.
Some time passes and a Walmart employee knocks and says "maintenance, any one in here?" And before I can respond the guy next to me let's out a massive loud as hell fart and the walmart employee without missing a beat says "take your time".