I don't think that you should have to explain yourself to anyone as to why you have that many cats. I don't understand why they think they need to give opinions--what you do in your home does not concern them. I guess I would ignore them if they brought up the cats--or totally change the subject on them. If I had a house--I would have more cats too. People don't understand that these animals are lucky to have a place to live and that you are doing a wonderful thing to provide for these kitties! Maybe you could tell them that if they are going to talk about the cats--then not to bother coming around. If they are true friends/family--they will support you in your decisions.