The New York Times vs Analytical Marxism, updated.

Economic segregation is a problem in preschool classrooms across the country. Decades of research show that poor children do much better academically in economically mixed classes than they do if they attend school only with other poor children. Research also shows that well-off children are not harmed academically by going to school with poor children.

repeats

For the Rengiers, the decision was clear: Their son would go to public school.
“It was not the question if we could afford it or not,” said Ms. Rengier, whose husband was transferred to the city because of his job as a lawyer and tax consultant. “It was a question of whether it was real life or not.”

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I wrote a book called "If you're an Egalitarian How Come You're so Rich?" And the final chapter discusses fourteen reasons people give for not giving away their money when they're rich but they profess belief in equality, twelve of which are, well, rubbish. I think there are two reasonable answers that a person who doesn't give too much of it away can give and one of them has to do with the burden of depressing yourself below the level of your peer group with whom you're shared a certain way of life; and in particular, depriving your children of things that the children around them favor. 

follow the link for the history. It ends up here, with links to the sources.