This post is popular not because it is accurate, but because it repeats the popular misconceptions about the US education system, and tells both left and right what they want to hear:

Of course, the biggest myth that the media reporting of PISA scores propagates is that the American public school system is horrible. The liberal left in U.S and in Europe loves this myth, because they get to demand more government spending, and at the same time get to gloat about how much smarter Europeans are than Americans. The right also kind of likes the myth, because they get to blame social problems on the government, and scare the public about Chinese competitiveness. We all know that Asian students beat Americans students, which "proves" that they must have a better education system. This inference is considered common sense among public intellectuals. Well, expect for the fact that Asian kids in the American school system actually score slightly better than Asian kids in North-East-Asia!

American students generally outperform their racial group in other countries. White Americans have higher PISA scores than any European country except statistical outlier Finland. Asian Americans beat every Asian country, and are second only to the wealthy, elite Chinese city of Shanghai (another statistical outlier).

Hispanic Americans are mostly Mexican-Americans, but outscore Mexico by a healthy 41 points. They are only 15 points behind Spain--and note that many Hispanic-Americans are recent immigrants and don't speak English as a first language (but had to take the test in English), while Spaniards take the test in Spanish.

African-Americans outperform Trinidad (Trinidad is a developed country with a high per capita GDP, and has a substantially African population, which makes them perhaps the most comparable group.)

This really seems to disconfirm both the liberal and conservative talking points. The US education system is not underfunded, as liberals say, nor is it underperforming, as conservatives say. It also is not correct that the US is systematically failing racial minorities due to institutionalized racism (as the OP claims).

The picture I have of the US education system is that there are a large number of smart, dedicated, people spending a lot of money trying get the best outcomes they can with the students they have to work with. This is all irreconcilable with the claims the OP makes.