Fiddlesticks, it's you who play semantics.
They are not palestinians, because there never was, in history a country named "Palestine".
It doesn't matter, Marguerite. If a group of a million people move into an area and decide to call themselves the nation of Santa Claus, then that is what they are despite the fact that it never existed before. Nations are born when people decide to form them. By that logic, during the Revolutionary War, the British could argue that there was no such thing as an "American" people, who had not previously existed as their own group since they were derivative English. Yet anyone making that argument today would be considered crazy.