My guess is they only sell babies young enough to still be super cuddly. Most baby parrots that are hand raised are going to be sweet, it is adolescent and adult birds that can be difficult, especially if they were not handled correctly at a young age. 90 days is long enough a to seem legit, but short enough that large parrots will not be hitting puberty yet. Making sweet babies is not hard, laying the foundation for sweet adults takes some work. This is a gimmick that allows the breeder to claim any issue is the owner's fault. At the same time, I would take a bird back that had a personality problem. I would not want it being sold off to someone else, I would want the opportunity as the breeder to evaluate what the problem was and what caused it. Many breeders disagree with the policy of taking the birds back, but is run blood tests and practice quarantine, and believe it is my responsibility as the person who provided the nest box, trained the baby, and chose the home.