Yes, I do agree.Transit, I sympathize with you not wanting to see things killed, but if it comes to killing one animal who is sick or watching your whole flock slowly suffer and die, I'm sorry, but off with their head.
I assume CMV and you would both probably agree that one quick death is far more humane than the whole flock of birds dying slowly. Altho I don't knpw much about the disease and how much suffering it inflicts, you do have to think about the long term good.
But in some cases, finches have been know to get Canker and end up just fine, Canker gone.