Add to these -isms open borders, globalism, Antifa, antiracism, anti-white ideology, U.S. civil rights movement activism (aka weaponizing blacks against whites), BLM activism, and so much more.
"No it's the leftists and liberals!"
Context helps….
Both quotes are authentic (accurately attributed and sourced). They come from real people expressing their own views, but neither represents mainstream Judaism, Jewish thought as a whole, or a coordinated “Jewish” position. Context matters a great deal. 
1. Rabbi Harry Waton (1939)
The quote is real and appears in his self-published book A Program for the Jews and an Answer to All Anti-Semites: A Program for Humanity (New York: Committee for the Preservation of the Jews / Astoria Press, 1939), roughly pages 99–100. Full surrounding text includes claims that Jews are the highest/most cultured people, that their destiny is spiritual mastery of the world through light/knowledge/humanity rather than force, and that “the races and the nations will cheerfully submit to the spiritual power of Judaism, and all will become Jews.” He also wrote that Judaism “gave birth to Marxism” and that the “communist soul is the soul of Judaism.” 
Who he was: Harry Waton (c. 1870/1871–1959) was a Russian-born American rabbi, kabbalist, and philosopher who emigrated around 1891. He was a committed religious Marxist/communist who blended Jewish mysticism, Spinoza, and Marxist ideas. He ran or was associated with small groups like the Spinoza Institute and the Committee for the Preservation of the Jews. His book was an eccentric, fringe response to rising Nazism and antisemitism—he argued that communism/internationalism/universal brotherhood was the true expression of Judaism and that Jews should lead humanity toward it spiritually. It met with widespread condemnation even at the time, including from other Jews.
He was not a mainstream rabbinic authority or representative of any major Jewish movement. 
Context and “true or not”: The words are his. The worldview they express (equating Judaism with communism and predicting spiritual conquest) is his personal synthesis, not traditional Judaism, Orthodox teaching, or the position of most Jews then or now. Traditional Judaism is particularist (covenant with one people, focus on Torah, mitzvot, and peoplehood), not a call for universal communist conversion. Waton’s ideas were fringe even among left-leaning Jews of the era. The book is sometimes circulated by antisemites as “proof” of Jewish communist conspiracy; it is better understood as the idiosyncratic output of one radical thinker.
2. Dennis Prager (circa 2020, and repeated elsewhere)
The quote is accurate and matches statements Prager has made multiple times. One close version appears in discussions around Jewish Learning Institute content or related interviews; very similar wording occurs in a TRIGGERnometry podcast and other talks: Jews who left belief in the divinity of the Torah adopted secular “religions,” and “if it’s an ism except Nazism, Jews helped found it and certainly helped lead it… Marxism, humanism, socialism, environmentalism, feminism… Jews.” He has said Jews are “the most religious people in the world but for most of them their religion is not Judaism”—they secularize messianic impulses into left-wing causes. 
Who he is and context: Prager is an American Jewish conservative radio host, author (Why the Jews?, Torah commentary series, etc.), and co-founder of PragerU. He is religiously observant (raised Modern Orthodox, remains committed to Torah-based Judaism) and a strong critic of the Jewish left and secular progressive “isms.” He frames the observation as a criticism and source of embarrassment: when Jews abandon traditional Judaism they disproportionately invent or lead utopian secular ideologies that often turn anti-Jewish or destructive. He explicitly contrasts this with authentic Judaism and ethical monotheism. It is not a boast of ethnic superiority or conspiracy; it is a lament about secularization and leftism among Jews. 
Context and “true or not”: The claim of disproportionate Jewish involvement in founding or early leadership of certain modern movements (Marxism/communism via Marx, Trotsky, etc.; elements of feminism, psychoanalysis, early environmentalism, various socialist currents) has a factual basis in historical overrepresentation relative to population size, especially among secular/intellectual Ashkenazi Jews in 19th–20th century Europe and America. This is well-documented by historians of all political stripes and is not unique to Prager. However:
• “Founded and/or led disproportionately” is true for some movements in specific periods and places; it is not true that “Jews” as a group founded them, nor that every major figure was Jewish, nor that this reflects Judaism itself.
• Nazism is correctly excepted (it was intensely antisemitic and racial).
• Correlation ≠ conspiracy or collective responsibility. High Jewish involvement in radical politics often tracked high literacy, urbanization, minority status, emancipation after centuries of restriction, and attraction to universalist ideologies promising equality. Many Jews also opposed these movements; religious and conservative Jews generally did.
• Prager’s point is cultural/religious, not racial: the pattern appears when Jews leave traditional Judaism.
Bottom line
• Waton: Authentic quote from a fringe 1939 religious-communist rabbi with idiosyncratic, universalist-Marxist views of Judaism. Not representative.
• Prager: Authentic quote from a contemporary conservative Jewish commentator observing (and criticizing) historical patterns of secular Jewish overrepresentation in left-wing “isms.” Not a claim of collective Jewish design or traditional Jewish teaching.
Neither quote proves a secret Jewish plot, that “Judaism is communism,” or that Jews as a people seek world conquest. They reflect individual (or, in Prager’s case, sociological) observations that can be and are selectively weaponized. Mainstream Judaism—Orthodox, Conservative, Reform, etc.—does not teach these things. Historical Jewish overrepresentation in certain intellectual and radical movements is real and explained by demography, culture, and history, not by the content of the Torah or a coordinated agenda.
