I don't think this tweet is bad at all. Say you're an American with Irish heritage. In 2022, you basically get all the privileges that white supremacy has to offer in this country (death to America btw).

But travel back in time to say, Manchester England in the 1840s. Had you been an Irish person in that social context, you absolutely would be experiencing a fair amount of ethnicity-based oppression and prejudice. Read about what the Irish lived through in that time and place. Even Engels, despite being completely sympathetic, ends up reflecting some of the prejudices of the time. Now, because you're an Irish-American, try putting yourself in those shoes. Might actually help you understand and empathize with current systems of oppression.

Would it be better to read about actual oppression and prejudice going on today towards the African-American community, indigenous people the world over, etc? Of course it would! But for a lot of people they need to imagine themselves in that situation to even begin to empathize.