Islam has a long history of racism. Out of that Arab racism arose a long history of the enslavement of black Africans by Muslim Arabs.
Islam is an Arab religion; despite the claims of Islam's 'universality'. For example, all Muslims must both dress like Arabs and have Arabic names. Muslim often tell us that the Koran 'can only be fully understood in Arab' and indeed that 'Allah only speaks Arabic'.
Of course the Leftist-whores-of-Islam have a theory which states that only (non-Leftist) white people can be racist (a racist view in itself) because 'only they have political power' (whatever that means). In fact, this is a positive racism towards brown Muslims used by the Leftist whores-of-Islam to rationalise and justify Muslim-Arab racism mainly (historically) towards African blacks, but also towards all non-Arabs and, racially, towards all non-Muslims.
The Left is racist to its core. It's just racist in slightly different ways to which Nazis are racist. E.g., it's racist towards whites; more specifically and usually towards the non-Leftist white working class. But in some ways Leftist racism is at one with Nazi racism - on Israel and the Jews, for example.
Leftist Jew-hatred pre-dates the foundation of Israel by over a hundred years and even predates the main beginnings of Zionism in the late 19th century. That Marxist, and sometimes socialist, racism was, well, racial and had nothing whatsoever to do with Zionism.
Like the Nazis, Leftists/Marxists make a strong connection between Jews and capitalism; even when Marx, a Jew-by-blood, made those connections. There's nothing strange about a Jew-by-blood becoming a Jew-hater. Many Bolsheviks were. So is Norman Finkelstein and Noam Chomsky today. Indeed they are only Jews 'only their parents’ side'. And race, these Leftists tell us, is irrelevant. I agree. So Chomsky and Marx being Jews is also irrelevant and shouldn’t be used by Leftists and Muslims to justify their hatred of the Jews or, indeed, their ‘anti-Zionism’.