Thank you Sacha for your considered reply. In order not to take up too much space, I hope that you will permit splitting up some points for reply.
On the in-joke. Jokes do not describe reality. They are a wry take on the world, very often with exageration to make a point. As an example, just look at Robin Williams doing the Scotsman and golf. But you raise it as a point. Very well. It was a joke I remember my dad telling me. And just to name-drop a little, to set the scene, my old man went out winching with John Maclean's daughter! Before, that is, my mother grabbed him!
So: here is a quote - albeit from Wikipedia - which slowly, slowly is getting better. Not the total joke it once was.
"On the eve of the February Revolution, in 1917, the Bolshevik party had about 23,000 members, of whom 364 were known to be ethnic Jews. Between 1917 and 1919, Jewish Bolshevik party leaders included Grigory Zinoviev, Moisei Uritsky, Lev Kamenev, Yakov Sverdlov, Grigory Sokolnikov, and Leon Trotsky. Lev Kamenev was of mixed ethnic Russian and Jewish parentage. Trotsky was also a member (or "Narkom") of the ruling Council of People's Commissars. Among the 23 Narkoms between 1923 and 1930, five were Jewish.
Conditions in Russia (1924) A Census - Bolsheviks by Ethnicity
According to the 1922 party census, there were 19,564 Jewish Bolsheviks, comprising 5.21% of the total. Jews made up 7.1% of members who had joined before October 1917.
Among members of the Central Executive Committee of the Congress of Soviets in 1929, there were 402 ethnic Russians, 95 Ukrainians, 55 Jews, 26 Latvians, 13 Poles, and 12 Germans – Jewish representation had declined from 60 members in 1927. With regards to Jewish representation in the ruling Politburo, it waned very rapidly starting in 1918. It began with the assassination of Moisei Uritsky, the most radical member of the Politburo, in August 1918. Then Yakov Sverdlov died of disease in March 1919 and Sokolnikov was shunted aside. Three years later in 1922, Jewish members in the Central Committee, the Politburo's new name, had shrunk to a minority of three: Trotsky, Zinoviev and Kamenev.