Adoptive relative is against adoption

This is an attitude and subsequent actions on the part of your adoptive aunt that were allowed to get out of hand by your adoptive parents. They should have had an in depth conversation with your aunt about the inappropriateness of her behavior towards you a long time ago just simply because it's unfeeling and mean. Then, they should have let her know that you are their child to them. Her behavior is obnoxious and odd. The only type of things I can see blood ties come into play over are family heirlooms. Example-A great great grandmother's item has been passed down for generations and it was meant to go to a descendant. I can understand a family wanting those types of items staying in the bloodline. You see this working in families with titles. Example-Earl and Duke. Adoptees can't inherit those. At least, that's my understanding. I don't have a problem with that.