First of all there is an anti-Semitic ground in the Turkish political culture. Most probably this anti-Semitic culture is based on the nationalist wave of the early 20th century, coupled with our famous “Sèvres Syndrome”. Founding fathers of the republic were not racist of course; but they were very open to influence of German intellectuals and political climate of pre WW2. There are a lot of evidence about anti-semitic attitudes of the early republican governments, from İnönü (1930s) to Peker (1945).
This anti-Semitic climate had an economic reasoning. “Establishing a national economy” was a common ideal of the early 20th century politicians, and “national” was “belonging to ethnic Turks”. First attempts of this approach to create “national riches” were observed during the WW1, under the rule of the Order and Progress. The Armenian genocide and the population exchange helped to create a basis for the new economic order. However, economic redistribution during the WW2 created a feeling of “unfairness” and Jewish merchant class presented as the target of rage against this unfairness, replicating western stereotypes of the rich Jewish “vampires”.
Moreover, Jews are always represented as parts of the International conspiracies, and Turks –perhaps everybody- like conspiracy theories. It is known that belief in CTs is highly correlated with a search of a meaning in an unfair and uncertain world. Grand children of the Otttomans try to explain their failure with conspiracies of the Western enemies.
Although Turkish politicians love to present Turkey as the host of Sephardic Jews; citizens of Turkey are nurtured in this very anti-Semitic environment. And almost every comparative survey shows that Turks are the most anti-Semitic nations in the world.
What makes this climate worth to use in their platforms?
Answer is highly related with the Palestine problem. As you know, until 1980s, the Palestine issue was advocated by the leftist fractions in Turkey and almost every leftist fraction was in contact with the PLO. The fight of Palestinians were presented as a war against the Imperialism –which was under the control of the Jews- and Arafat was a national hero, very similar to Atatürk. Consequently, there is an abundant environment for anti-Israel arguments in the left wing of the spectrum.
During 1970s, the Milli Görüş movement was also very sympathetic towards the Palestinian issue –they were anti-semitic in born not surprisingly- and their Third Worldist ideology was including a natural reaction against Israel and the US. However, since the fight against the communism was the dominant theme during 1970s for the Turkish nationalism, criticism against the US and its natural ally Israel wasn’t popular.
With 1980s, traditional Turkish right started to openly support the PLO under the rule of Turgut Özal –a center-right politician from the Milli Görüş movement-. The Intifada provided a lot of reasons to support the Palestinian cause and appealed the support of the center right, who were traditionally sympathetic towards Israel and the Western world.
The Kemalist segment of the society –the most educated and westernized one- is generally skeptic towards the Arabs and tended to see Israel as the island of modernity in the swamp of the Middle East. However, the Palestinian issue and traditional xenophobia –more educated, more xenophobic- of this segment created an anti-Israel and anti-Semitic ground in this segment of populace. Moreover, conspiracy theories about the support of the Israeli governments to the PKK and the Kurdish movement are very popular among this segment.
As you can easily observe, almost every constituency in the Turkish political scene has a reason for buying anti-Israel and anti-Semitic arguments; hence, politicians don’t hesitate to use them for their own interest.