Lol Hlau already addressed the Palestinians not being an ethnic group propaganda you said. I mean where is your evidence for this dumb claim. What if someone claims modern day Israeli or Americans aren’t an ethnic group define that.
Actually we did; the the Nazis were Germany. Mostly unwillingly on the part of most Germans, true; but that resistance wouldn't have lasted if we hadn't invaded. Eventually, efforts like the Hitler Youth would have brainwashed future generations into blind obedience to Nazi ideology. When we destroyed the Nazis, we destroyed the then-dominant culture of Germany, and forever changed them as a people.
How successful that would be is hard to say. We have similar, longer running efforts in North Korea, PRC and Soviet Union to compare, and the results vary a lot.
However, with the Palestinian situation it is even more complicated. It is a similar "Islamic North Korea" mess with media and education ran by militant organizations over decades with their own recruitment interests in mind, but there is also another layer to the problem - very recent history.
Lets start with few quotes:
Zuheir Mohse, high ranking PLO official, 1977:
"The Palestinian people does not exist. The creation of a Palestinian state is only a means for continuing our struggle against the state of Israel for our Arab unity. In reality, today there is no difference between Jordanians, Palestinians, Syrians and Lebanese. Only for political and tactical reasons do we speak today about the existence of a Palestinian people, since Arab national interests demand that we posit the existence of a distinct Palestinian people to oppose Zionism."
"For tactical reasons, Jordan, which is a sovereign state with defined borders, cannot raise claims to Haifa and Jaffa, while as a Palestinian, I can undoubtedly demand Haifa, Jaffa, Beer-Sheva and Jerusalem. However, the moment we reclaim our right to all of Palestine, we will not wait even a minute to unite Palestine and Jordan."
Prince Hassan of the Jordanian National Assembly, 1970
“Palestine is Jordan and Jordan is Palestine; there is only one land, with one history and one and the same fate.”
Auni Bey Abdul-Hadi, an Arab Muslim leader, to Peel Commission in 1937
“There is no such country as Palestine! ‘Palestine’ is a term the Zionists invented! There is no Palestine in the Bible. Our country was for centuries part of Syria.”
Syrian President Hafez Assad to Yasser Arafat
“You do not represent Palestine as much as we do. Never forget this one point: There is no such thing as a Palestinian people, there is no Palestinian entity, there is only Syria. You are an integral part of the Syrian people, Palestine is an integral part of Syria. Therefore it is we, the Syrian authorities, who are the true representatives of the Palestinian people.”
The people whose quotes i've selected here aren't Zionists saying these things for their own advantage in the conflict, those are leaders of Palestinians and their Arab allies at arms (absolutely no coincidence there).
And something less usual, mentions of "Palestinian people" in written material recorded by Google:
Google Books Ngram Viewer
books.google.com
The conclusion is clear. The supposed "Palestinian people" are just Arabs, most closely related to Arabs of Syria and Jordan, tactically rebranding themselves for political reasons, roughly half a century ago. They aren't a separate ethnic group any more than East Germans and West Germans were, or North Koreans and South Koreans are. Possibly less so, as the latter had spent a long time living under distinct and conflicting ideologies and international power blocks, while the Palestinian brand of Arab Nationalism and later Islamism are just a different, sometimes more extreme variation of movements that were fairly notable if not leading in the nearby Arab countries at the same time. After all, if Palestinians are not Arabs, why the hell did Arabs fight several wars for them? On the other hand, it makes a lot of sense for them to fight several wars for fellow Arabs. We know what relations do Arabs of the region have with the distinctly non-Arab ethnic groups of the region, even the Muslim ones like Kurds, Turks or Persians, and its unheard of for them to be so helpful and charitable to those over long periods of time with no clear and big reward in sight.