Linear decent can focus our interests, so that we can seek out connections and build on them, but the only connections aren't to do with descent, and we shouldn't allow that kind of thing to limit our horizons, or try to do the same to other people.

And what right have we to "reject the falsity" of people who choose to adopt a culture to which they were not born?   People living within that culture might have that right, but they might just as soon see that decision as something to welcome.

The same goes for children of immigrant families, whether from Scotland or Sierra Leone, who either choose to hold on to aspects of their heritage, or adopt the culture of their country of birth (or indeed some other culture).

Plus of course most people have quite a range of cultures among their forebears. They may choose to select one particular one, they mat choose to mix and match.