It's interesting how many people missed the point of the article.
It's not that talking about the 1950s misses the point due to Jim Crow. It's that many of the benefits white Americans received after the war were made possible by Jim Crow. The massively-expanded university access still had very little African-American competitions for those slots, as did the famously good-paying factory jobs of the 1950s. Talking about how much better things were then ignores the fact that much of the good quality of life for white Americans originated with Jim Crow and its more subtle northern cousins. African-Americans can get a hint when you start talking about that era as a better one that you don't have their best interests at heart.
The article just mentioned that idea in passing and didn't provide any evidence for Jim Crow as a major factor for white opportunity in the 1950s.