I don't find the humor in it because it happens all to often and is not a "funny" topic.
I guess this is where I stand on this topic as well. I was under the impression that even practical jokes were supposed to have an element of humor about them, but I kept trying to figure out what exactly was so funny about dragging family pets to the shelter- where thousands die every year. Maybe it's just because I volunteer at a shelter where I see this EXACT scenario played out time after time- the reasons for surrender "they're too expensive," "it was just getting to be too much," or even "we got new furniture and they didn't match," those are all reasons I've actually SEEN. And I've seen those same dogs take a one way walk down the hallway- dogs that were at one time, loved family members, dogs that as I groomed and bathed them, were perfect ladies and gentlemen, offering kisses, sitting still for nail clippings, and performing tricks for treats.
I dunno, maybe after a few years of seeing that, even joking about it stops being funny. Sorry to be a killjoy, it's just how I feel. However, glad that all your pups are safe and sound.