Oh - can well believe it.
I have commented in other posts that I would hate to be the vets who had to euthanise healthy dogs. Even when animals have bitten and can be considered a danger, it can't be easy. When they are dogs that have never done anything, and with a good owner possibly would never do anything, or particularly when these are tiny, helpless puppies, it must be heartbreaking.
Knowing it is necessary must barely blunt the horror. Your daughter and other vets in this position have my deepest sympathy - especially as those dogs being brought for euthanasia are probably, by definition, animals from responsible homes.
Many will just be abandoned, or drowned etc to save the cost of PTS. It isn't the fault of all of the dogs, but because of the way they are bred, and of many of the owners, they can't be trusted.
But I absolutely agree that this is a horrendous situation for the vets involved. Absolutely dreadful!