Hi.

During Deir Yassin, there was not yet an Israeli government. There were three main Jewish groups fighting in the civil war begun in 1947 against Arab militias and against Arab "volunteers" from other Arab states.

The first, Haganah, was by far the largest. Its forces would become the backbone of the IDF, and its leaders would essentially run Israel for nearly 30 years through electoral dominance.

The second, Irgun, was smaller but more extreme. It would be dissolved and integrated into the IDF, following a violent incident with the Haganah, and its forces were forcibly separated so as to prevent independent activities by former Irgun units.

The smallest was Lehi, an offshoot of Irgun. They were by far the most extreme but numbered no more than a few hundred at their peak, while Irgun reached a few thousand and Haganah reached into the tens of thousands.

The Deir Yassin massacre was carried out by Irgun forces, primarily, with the intent of scaring away Arab villages with the word of the massacre. The Haganah condemned it, while Lehi actively participated.

The massacre was indeed exaggerated. The PBS documentary 50 Years of War interviewed a former Palestinian radio broadcaster. He said he spoke of rape and inflated brutality, with the Arab leadership hoping this would spur people to fight the Jewish militias with increased intensity to defend their homes and families. It had the opposite effect, going the way Irgun preferred and causing more people to flee.

That's not to say it didn't happen, and the Nakba certainly happened too. Deir Yassin still saw what is today estimated to be around 110 casualties, half of them civilians who were likely executed or carelessly killed in the fighting. However, this is shy of initial estimates believed to rely on double counting and exaggeration, of around 250 deaths. The new count was crafted by historians who spoke to those there and investigated the matter further starting in the 1980s. The Nakba likewise occurred; it refers to the fleeing and expulsion of 710,000 Arabs living in what became Israel. This is not to say expulsions or flight went only one way, or that it was official Israeli policy; rather, individual Israeli commanders in the field had the control over what to do, and made their own decisions. Thus, commanders in the north would do things quite differently than those in the south, based on their interpretation of military necessity and their own beliefs/desires. The same occurred in Arab countries like Iraq, where leaders handled the Jewish exodus differently from Jordan's handling in Jerusalem.

There are indications the Hadassah massacre was partially a revenge attack for Deir Yassin, including witness recollections of statements by the attackers like "for Deir Yassin".