Any country needs an identity - otherwise it sooner or later gets relegated (implicitly or explicitly) to region of another. It doesn't take long to notice that current Greece isn't ancient Greece. But there are enough reasons to grant a relatively larger tie to it than for people who are not from here.Nationalism is a very modern invention, and all in all an artificial construction,
the history of the city of Gent for example predates the history of the nation state of Belgium by many centuries, arguably I'm more "linked" to the people that walked these same streets 500 years or a 1000 years ago, than to some Belgians in the 1800s.
In Greece your cities are many times older even, isn't it much the same there ?
As for the 1821- greek state, historically it tried to restore its byzantine center. This was virtually achieved in 1919-1920, but then got away again.
Among other issues, one prevalent in greek society is that there is literally so much history tied to cities and areas, that while you can easily identify with various majestic things, the overall culture (to the degree we can speak of an overall culture in any country) is very much confused.
Some emblematic parts of civilization, simply transcend borders. Again, not difficult to find, even if you don't actually mean to look for them.
(PS: it wasn't called "trap" by the author; that's just some lowly american naming ^^ )