If we are going to attempt to rehome then obviously its better to rehome the ones without problems. But (to make an extreme comparison) - I wouldn't advise not rehoming a fear aggressive 7 year old homeless human because he/she's been in a few fights. That's because I'm human, and I have an instinct to protect my kin. However, rationally, I have no reason to believe that humans are any more deserving of life on earth than any other animal is. Advising the death of an animal that has not caused significant harm (and muffy hasnt) would cause a serious conflict within me, especially one that is shaping up to be be a better pet than many other successfully rehomed animals. I'm quite glad its not my responsibility to run a shelter.