I am afraid that you are incorrect on this point kosta. Hellenization was very evident among Jews in Israel. Where do you think "Decapolis" came from (Mt 4:25, Mk 5:20; 7:31) and pigs. Different sects within Judaism at the time responded differently, zealots resisted strongly, the sadducees were favorably inclined towards it. The common man felt both sides of the tension, being hellenized to various degrees based upon location and social status.
Also, kosta, you forget the Jews of Ethiopia and India and Yemen -- all outside the Hellenic world and all by and large untouched by Hellenizm. Christianity spread over there pretty well among the Jews/Israelites in those places
No doubt, just as the world is Americanized today. That doesn't mean the world has a sophisticated knowledge of the English language down to the common farmer. They are familiar with brands and have the ability to communicate. In the Middle East very few people actually speak English.
Your average Greek fisherman doesn't speak English, neither does your average Spanish farmer. Your average Moroccan cazba merchant may be able to offer his items in several broken European languages, but not hold a political or philosophical discourse in any.
The Hellenization came, of course, from Alexander the Great and his conquest. But the nature of the Jewish culture was such as to prohibit mixing with the Gentiles, eating with them, etc., so the direct contact was much more limited, the exchange of information also, and education was reserved for a few and far in between.
To simply assume the Palestinian Jews were fluent Greek speakers, or that they would preferably write in Greek than in Aramaic for other Jews is far fetched. The situation with Jewish Diaspora in Egypt and Asia Minor was different. They lost their language and spoke and wrote in Greek the way American Jews speak and write in English.