That is a disgrace. “Euthanasia” is death that is in the interest of the human or nonhuman euthanized. Euthanasia is never in the interests of a healthy being.Why assume the animals were healthy? This is what Ingrid Newkirk wrote, after an anti-animal-rights group started a campaign about how PETA kills animals (I discussed the campaign here).
Second, he surmises that PETA accepts a theory he attributes to Peter Singer.
PETA apparently shares Peter Singer’s view that a relatively painless death does not constitute a harm for nonhuman animals because, unlike humans, most nonhumans are not self-aware and cannot grasp what it means to “have a life.” In order to have an interest in your continued existence, you must be human. So those 2352 animals that PETA killed weren’t really harmed. They did not care about their lives anyway. Nothing was taken from them when they were killed.But this isn't even Singer's theory, His theory is that death harms human beings in more ways than it harms animals, not that death doesn't harm animals at all. For a human and an animal, death harms by taking away future satisfactions. Death merely harms humans in an extra way, by taking away satisfactions they explicitly want.
This difference does have some practical implcations. If you could run a farm where animals are painlessly killed and bred, so that every bit of happiness lost was replaced, Singer thinks that would be different from running a people farm. The absence of desires about the future makes animals (of most species) replaceable. But euthanizing animals at a shelter doesn't involve the combination of killing and replacing. So Singer's "replacement argument" has no relevance.