Trotsky (Bronstein) was Jewish and I think Lenin was 1/4 Jewish ethnically. Stalin (Dzhugashvili) was Georgian. Perhaps Stalin and Trotsky used their revolutionary names to deemphasize their ethnic backgrounds.
I don’t think anyone has claimed Stalin had any Jewish background.
Stalin had been a seminary student and that might be partly why he seemed to regard any deviation from his party line as heresy.
___
Racist Arab "Palestinian" leader Mahmoud Abbas Abu Mazen - did in 2018...
European Jews, Abbas said in Ramallah, ... Palestinian Authority president went on to say that the Soviet despot Joseph Stalin, who was not Jewish, was in fact [sic] a Jew ...
The Palestinian Authority chairman retracted what he said this week in Ramallah, which caused a storm in Israel and around the world: "The Holocaust is the most heinous crime in history."
Palestinian Authority Chairman Abu Mazen apologized to Jews today (Friday), following his antisemitic remarks earlier this week, during a Palestinian National Council meeting that caused a stir and condemnation in Israel and around the world. He said that "I did not mean to offend the Jews, I feel respect for the Jewish religion." He went on to call the Holocaust "the most heinous crime in history."
Defense Minister Avigdor Lieberman commented and tweeted on his Twitter account that "Abu Mazen is a poor Holocaust denier, who wrote a doctorate on Holocaust denial and then also published a book on Holocaust denial. This is how he should be treated. His apology is not accepted."
Abu Mazen cited as evidence the words of "three [supposed] Jews", including none other than the Soviet dictator Josef Stalin (who was not Jewish) ... Abu Mazen added, ignoring the blood libel in Damascus in the 19th century and the Farhud riots in Iraq in 1941, that "Jews have lived in Arab countries for years, and for 1,400 years no action was taken against the Jews because they were Jews."