The things you want them to talk about are perfectly reasonable things to talk about, but they don't have much to do with the article and I don't see how their absence means that "the author oversimplified their argument". What argument do you think the author is making that would have been made better by talking about reparations, or a "black tax" in the sense (completely unrelated to that of the title) of tax imposed to finance reparations, or systemic racism on the part of the US government?

I think the article is trying to do two things. One of them -- sharing some aspects of the author's experience as a black entrepreneur that many readers will likely have no inkling of -- doesn't involve any argument at all. The other is objecting to criticisms of the idea of a "wealth tax", on the basis that lots of people are already facing a "tax" that will likely stop them becoming wealthy, and it doesn't stop them working hard. The things you want the article to mention wouldn't have had any relevance to either of those.