Ms. McGhee's point is that racism hurts us all, and she uses a very real example. From the 1910s through the 1950s, American cities competed often for prestige infrastructure projects. Her example are Public Pools throughout the country during this time. Then, in the 1950s and 1960s, cities were ordered to integrate what had been "whites only" places.
Rather than open to all people, many cities (St. Louis, Birmingham, etc) opted to close the pools instead of integrate. She expands this to include many aspects of life in this time (I would include the reasonable cost of University through the 1970s to that). Different choices that would close public options rather than integrate them.
She makes the point, eloquently, that racists often see these matters in terms of zero-sum games. That is, if black people can come to the pool, then white people are somehow losing something. She postulates that this zero-sum thinking is what has hampered the south, and now much of the country lets infrastructure fall apart because building better schools, roads or hospitals helps all people, including black and brown people and how racists somehow see that taking away something from black people.
Right after reading a bit more about this phenomena this morning, I see this from Ted Cruz online. First, it is a lie, undocumented immigrants do not get checks. But second, what vote against supporting 29 Million Texans because some undocumented immigrants might receive money to live (even though they won't). Accidentally increasing the pot and giving some money back to immigrants IF THEY PAID taxes, while not burdening any natural born-Texans or legal immigrants, that tiny percentage that MIGHT get funds is enough to deny payment and extended unemployment to all Americans.
Loudly cheering on hurting immigrants, even if it also hurts locals, is somehow a wining strategy for Texan politicians. It is fucked up. Giving a little extra, doesn't hurt anyone else.
And, if you think the budget deficit is a good reason to NOT give that money, I would argue the BILLIONS of dollars in tax breaks to multi-millionaires under the (last 2) Republican Administration is a much worse deal for the country, both racists and non-racist.