Welcome to G2G forum Lucy.
That is because "They (The Non-Biological indicators) do not currently appear on profiles or other family tree views."
(See What Does this Setting Do?)
Usually a related note is added to the Bio/Sources section of the profile representing an adopted person.
There is a template you can use for this purpose. You can see how the template looks going to the bottom of the page.
If you decide to use the template, there is no need to know/enter all the parameters. Missing parameter will return unknown.
If you don't want George's adoptive parents appearing as his ancestors you would have to remove them as his parents.
Please post any other doubt you may have.