It's my understanding that:
The term "Palestine" refers to a geographic region in the Middle East that includes the Gaza Strip, the West Bank, and Israel. The term comes from the Philistines, an ancient people who lived on the coast of what is now Israel and the Gaza Strip. The Romans reapplied the term to the region after defeating the final Judean uprising in 135 CE. Romans renamed Judea to Syria Palestina, which was later shortened to Palestine in the early 2nd century CE to suppress Jewish nationalism. More than a century after Jesus was crucified.
The term "Palestinian" refers to the Arabs who live in the region of Palestine. The term was first used by Khalil Beidas in 1898 in the preface of a book he translated. The Arabs of Palestine began to use the term more widely in the pre-World War I period. After 1948, the term came to signify a sense of shared past and future for Palestinians.
Jesus was born into a Jewish family in Judea long before the region was given the name Palestina by the Romans.
If the Pope wants to show sympathy to the people of Gaza, I have no objection. If he wants to console the relatives of all the hostages taken on 7th of October, I have no objection. But to politicise a nativity scene, allowing the addition of a keffiyeh scarf, suggesting—yet again—that Jesus was a Palestinian is ridiculous and wrong.
You probably think this gesture showed solidarity with Palestinians and reinforced your belief that Jesus was a Palestinian not a Jew. Well all it achieved was to create more division. As a Christian he is meant to unite people of all faith not undermine his own churches doctrine.