So whats the solution?
I feel bad for the person who has to work in this every day, but regardless, there ARE circumstances where its unavoidable and you have to take the animal to the shelter.
Divorce happens...people move from houses into apartments. Not all apartments allow pets, and the ones that do, typically don't allow large breed dogs like German Shepherds, or Rottweilers.
Owners die and no one can take the pet thats left behind. I adopted a beagle from a shelter whose owner died and no one in the surviving family could take the dog.
Some animals can develop problems that can't be fixed through medicine or other care and they can no longer be compatible with humans. Aggression, incontinence, destructive behavior. I had a cat for 7 years that one day stopped using the litter box and started pissing all over the house. Despite almost a thousand dollars in vet bills, and a year of trying different solutions, the cat would not stop pissing all over the house. And after a year of it, and not being able to live another day walking into my home right into the stench of cat piss, I had to get rid of the cat. I couldn't pawn this problem off on someone else, so I had to take it to a shelter. Broke my heart but had to be done. Also had to replace $3000 worth of carpet padding and subfloor just to eliminate the smell.
I really do feel bad for people that have to deal with this day in and day out, but not everyone that has to surrender a pet does so because they are simply tired of it.