We once had a dog which we gave away at 1 year old. I did feel like there were better options (training) though at the end of the day it was not my decision to make and I was not there when it attacked our 13 year old collie. I think its give and take in these situations, we took in a pekinese and a red heeler for the rest of their life when their owners couldn't keep them and the pekinese had been with it's previous owner for a very long time. The problems start when people take in cute puppies and take them to shelters when their older and would never consider any dog other then one they bought. So long as people are willing to help the situation I don't see a problem with it.
I'm lucky to live in an area where most people are responsible dog owners and don't abandon/breed them.
Main message again, it's all about give and take