Since the First World War there has emerged the fragmentation and weakening of the Arab world, such as the Sykes-Picot agreement and the Balfour Declaration, and the Palestinians pay the price. Instead of Palestine being a natural part of Syria, a major state that could be in a position to confront the Zionist entity, it was isolated from the motherland in order to weaken it.
Did you catch that? Jabbour admits that "Palestine" was never an independent entity and is naturally a part of Syria! The tragedy he is lamenting is the very same event that gave rise to the beginnings of Palestinian Arab nationalism - before 1920, practically the only nationalism any Arab spoke about was for Greater Syria, with nary a word for "Palestine."
Reading these words you can see that Palestinian Arab nationalism is an artificial construct, borne out of the desire to thwart Jewish nationalism and not at all to help Palestinian Arabs achieve their national aspirations. They didn't have any.
We all knew this, of course - the infamous antisemitic Mufti of Jerusalem only became a Palestinian Arab nationalist after Sykes-Picot - but it is interesting to note that even today's Arabs know this as well, even if they never will admit it in English.