I wouldn’t consider throwing a bunch of frightened animals into a gas chamber at once humane or even ethical, but in the same breath I can consider the cost effectiveness and the speediness of the process. It costs a lot less to gas a whole group of animals together than it would to gas each one individually and it is significantly less costly than to administer the lethal injection to each animal individually. Many shelters just do not have the space or the funding to accommodate all of those animals, from the youngest newborn litters to the elderly or even to the special needs, so in order to make room for new animals they need to clear out the ones not being adopted.
It’s not a matter of the employees wanting to kill animals or not caring enough about their animals; it’s just not within their power to do much of anything about it. You need to consider the whole picture when you come across videos and information like this. There are hundreds of thousands of strays possibly right here in the United States alone. I could be stressing that a bit, but my point still remains and I will continue my example. With the amount of animals coming into shelters from negligent breeding, feral strays, lost pets, abandoned pets, pets left without an owner due to death of the family/allergies within the family/et cetera, and various other ways each and every day how do you expect the facility to keep up with the influx when they only have a designated amount of room and funding available to house, feed, clean, provide medical care, vaccinations, altering, and so on?
No-kill shelters can be hard to come by and they are hard to keep around because it takes cooperation from other no-kill shelters and adoption-availability establishments (like Chuck & Don’s, Petco, and Petsmart) to shift their animals around from place to place and then there’s the donations from the community to help fund their causes, provide such care, and so on. If there’s no cooperation, no donation, no time given, and too much negligence then you will find that facilities need to do what they can to ensure the healthier or fresher faces have a fighting chance when the ones that went over the allotted timeline, or the sickly, elderly, and special needs, have to be cleared out to make such room.
How about instead of blaming the shelters and trying to outlaw their last practice of defense to keep their shelters open and available for the animals we go ahead and try to educate owners about the negligence of allowing their animals to roam unsupervised, the importance of spaying and neutering your animals, and considering the responsibilities of actually owning an animal. Unfortunate circumstances happen in any situation, so if an animal needs to be rehomed because of a death then obviously blame cannot befall the owner, but dropping off your animal at the shelter because “it peed on the carpet and I just don’t want to deal with it anymore” is a half-assed excuse from an owner that didn’t want to put forth the effort to learn. But if we can educate owners the importance of animal care, catching ferals/strays and bringing them in to be altered, altering your own animal if it is not necessary for them to remain intact (shows, work, breeding, et cetera), leaving the breeding to professionals, and bringing awareness about donating to your local shelter to keep them running, well-funded, and clean then there would be no need for gas chambers to clear out groups at a time.