Exceptions, theone? It's more than just an "exception. Palestinians played a major role in organizing and shaping the political and armed wing of the FMLN. And if you really want to learn more of progressive Palestinians throughout the world, check out the history of the Chilean Palestinians. If I am not mistaken, there are close to 750, 000 Palestinians in Chile, MANY of whom are progressive.

https://www.nbcnews.com/news/latino/chiles-large-palestinian-community-criticizes-israel-gaza-rcna123888