It doesn't necessarily directly starve the other dogs, they'll have less energy to attempt to reproduce with. It's not an attempt to increase the death rate as much as it is an attempt to decrease the birth rate.
My "also, wtf" stands.
My "also, wtf" stands.
If I may make an attempt at the moral underpinning, it is something like "survival as intrinsic worth". There are flaws to this position, as with any.
Granted, there are times when euthanasia would be necessary. For example, feral dog populations in areas where the vulture population has died off, where they carry disease and attack passersby and the supply of food is basically uncontrollable, I get it. But that's a case I personally would preemptively qualify if I were considering it.