Sadly, there seems to be an unreasonable standard that expects an adoptee to be grateful to the people who adopted them for having saved them from a worse fate.
Generally speaking gratitude is an important spiritual practice in my own life but I get it.
In truth, while parents are mostly grateful to have received the children born to them and to have the complicated, difficult and ultimately satisfying job of mentoring the next generation into the ways of the world until they are able to navigate it on their own, that does not mean that their children are obligated to be grateful to their parents for having done what parents are supposed to do.
An adoptee has a complicated situation. They are expected to give up any attachment to the people who gave them birth, allowed to have the basic details of their identify changed and more accurately falsified and then expected to be forever grateful to the strangers who took them in and raised them.
This is not a realistic expectation. I understand so much, so much better now, that learning about my own parents’ adoptions has also encouraged me to learn more deeply about all aspects of this human practice.