This article has a pretty bad smell. The author makes a lot of fairly extreme claims but these are mostly based on his own anecdotes or non public data sets. The claims that
"you can separate all advanced math teachers easily into two categories: Okay with blacks in their classroom [...] Not okay with blacks in their classroom. Whites end up succeeding, blacks end up failing"
and
"the evidence shows that teacher recommendations have zero correlation with aptitude in a field"
are really quite dubious and almost certainly false. How did they measure whether they were "okay with blacks in their classroom"? As many others have said in the original thread, this is probably a hoax.
"you can separate all advanced math teachers easily into two categories: Okay with blacks in their classroom [...] Not okay with blacks in their classroom. Whites end up succeeding, blacks end up failing"
and
"the evidence shows that teacher recommendations have zero correlation with aptitude in a field"
are really quite dubious and almost certainly false. How did they measure whether they were "okay with blacks in their classroom"? As many others have said in the original thread, this is probably a hoax.