In 1969, I was 18, living in Poland, and was already vividly interested in politics.
Socialism did not work, and the nation was under many economic and political pressures, which exploded during the bloody riots in December of 1970. As a Gdańsk resident, I lived through it.
At that time, many Poles of Jewish ancestry held top positions in the ruling party, government administration, and the military. It was because, in their youth, they were active in socialist organizations, which later took power.
Inside the ruling elites were many factions and conflicts. Some were about political concepts; many were about access to privileges that top government jobs provided. In particular, accusations of disloyalty were a common method to eliminate a political opponent or vacate a lucrative position so a friend or a family member could get it. For example, someone in a prominent position could lose a job for attending church. Catholic Church was considered the enemy of the system.
In the Six-Day War of 1967, the Soviet Union supported Arabs, and so did Poland as a part of the Soviet Bloc. One can understand that Poles of Jewish ancestry sympathized with Israel. There were rumors about lavish parties where Polish Jews from the government elites celebrated Israel’s victory. I do not know how big those parties were, but I can believe that at least some had a toast congratulating Israel.
As a result, the issue of loyalty of Polish Jews to the Soviet-supported Polish ruling elites became an issue. By the way, it was the same in the Soviet Union, and comrades from there pressured Poles to address that “problem.” Many Polish Jews lost their prominent jobs; some were pushed to emigrate. But it had nothing to do with antisemitism. It was a part of the Soviet system, where, at some point, Polish Jews found themselves on the wrong side.