Unfortunately, the reality is that shelters euthanize animals - plain and simple. Even if they don't euthanize for space issues, they all euthanize ill and anti social animals.
There are over half a million stray cats on the streets of Toronto, with dozens more being surrendered to shelters and animal control on a weekly basis. This IS NOT going to stop, it is just getting worse and worse each year. Don't blame the shelters because they are the last people who should be taking the blame for members of our community being irresponsible with their companion animals. It is up to every one of us to ensure that euthanization technicians are out of a job in the future because it is members of our community who are the ones who guarantee they have jobs to go to.
The only animals that I know of that are being put down are special needs animals that will require, sometimes expensive and intense, medical attention for the remainder of their lives and animals that have extreme aggression issues. Some of these animals have been kept in cages for literally years - cages no larger than you would find in a puppy/kitten mill. They don't have any quality of life and they just aren't getting adopted or fostered.
Some of them are getting out because they are in peril, and that is great, but no shelter can be in a position where they close their doors to animals coming in because their cages are full of sick and aggressive animals - which is exactly what has been happening down there. The THS became the equivalent of a large scale hoarder - taking in completely unadoptable and sick animals and not being able to keep up with their care or unable to provide any quality of life at all.
If people are outraged, that's good because you can put your anger to good use here. Don't buy animals from petstores and breeders. Don't shop in ANY petstores that sell ANY types of animals. Spay and neuter ALL your cats and dogs and don't let them out to roam the streets. Encourage friends/family/coworkers/forum and internet friends to always consider adopting an animal from a local shelter if they are searching for a companion. If you can foster, then go in and sign yourself up. If you can provide an appropriate home for a special needs animal, then adopt one because almost no homes turn down young, healthy animals for special needs ones. Put all that anger and frustration to good use and get animals out of shelters and into homes because euthanization is not going to end any time soon.