What that vet tech said was extremely unprofessional. I don't know if they're aware of the stress owners can go through with euthanasia. I've twice asked a vet "if this were your pet, what would you do?", both times the vet avoided answering only giving risks and likelihood, which is the professional thing to do.
Older dogs are at higher risk for anesthesia, I'm sure that and the dogs general health were reasons, that said, it's very easy to make cold emotionless calls on an animal you have no attachment to. But your dog survived surgery and can now get a more peaceful planned euthanasia. IMO, you're making great and compassionate choices all around for your baby. 99% of dogs don't get the unconditional love you have selflessly provided.