What Prince William did here was admirable. And I have seen stories of less famous, but still influential, people similarly helping Afghans to get out. Kudos to them, too!
Still, the fact that the Prince's intervention was needed to save this person and his family is a damning indictment of the way the US and our allies managed the withdrawal process. If you have a friend at court (in this case, an actual prince!), you could make it. The many refugees who don't have such contacts were all too often out of luck.
Some people might feel that this meant someone else got "bumped" off and that he could send more RAF planes to help evacuate more people. Of course, this assumes that the person who would have potentially got "bumped" off would have otherwise actually taken the seat.
In reality, my understanding is that many of the planes taking off were not infact completely full. Most could have taken additional people.
This is deeply unjust for pretty obvious reasons. You don't have to be as radical about immigration and refugee issues as I am to see why.