Well, as long as we're going down this line of thought let's remove all of the other unnecessary bits. That tail, for example....I've seen an awful lot of injuries to it, so let's prevent those by removing it. Those ears, especially on some of the large lops, are too big and prone to infection and tearing. Let's remove half of them to prevent this.

If someone is breeding their rabbit wisely, carefully, and to a good end, I see no reason to alter the rabbit. I had a Mini Lop doe for nine years, outdoors, who was not altered. She lived in good health (Except for one non-feeding scare, but the cause of that was quickly found and fixed) and happiness for all of those nine years, right up until the last few days.