I have never minded the term "mutt" because that is what I am myself. I have always referred to myself as one, or Heinz 57. But I have never heard anything negative on YT about mixed breeds other than the purposeful breeding of them. I think we can all say that we have had some wonderful mixed breeds in our lives, and my two grand-puppies are mixed breeds. One is the cutest dog, with a head of a beagle and the body of a pointer! Everyone laughs, and I love it! He is the cutest dog I know!