I'm not sure your thinking on this is entirely fair to Jessie's mother.

Parents are humans too, and they make mistakes and have ideas that are wrong and change over time, as everyone does - they are fallible. Caring parents want the best for their kids, even if they don't really know what that is. No mother was given an accurate parenting playbook.

Parents and kids hide many things from each other: as for the parents, the less than noble parts of their histories; as for kids, their wants and desires that are not always in sync with the expectations of their parents.

Excommunication is a punishment unless it is there to prevent serious psychological damage. Forgiveness typically benefits the foregiver more than the foregiven.

In time, Jessie should consider the benefit to herself of reconciling with the only mother she will ever have.