Where I went to school, nothing was dumbed down, but students were separated into sections depending on academic and standardized test scores.
Classes were integrated, still, but those not left behind were taught at a more appropriate level and those who were ahead stayed there.
Now, the mix has been shuffled to keep the fastest held back with the slowest (self-esteem stuff), and a sad result is that many bright kids who might have done well get bored out of their tree, have no options, and end up either getting in trouble or just quitting.
I graduated in 1969 in the deep south. We integrated my senior year. The black kids were given a choice as to which school to go to. I think it was 6 black kids who came to the white school. There was no problem and most of us became friends. At our 30 years HS reunion one of the black girls showed up and I hugged her and kissed her on the cheek. I did get a few stares.
The next year they integrated all 12 grades. They attempted to make everything equal. Back in those days the students voted for the cheerleaders. But they decided that there would be 4 black cheerleaders and four white cheerleaders. And they dumbed down the passing requirements. In 1969 we had to make 70% to pass. The next year they dropped it to 60% and kept getting lower. Now I think everyone passes if they show up.
Now it’s hard to find a teacher who can speak English or knows anything about politics. Remember the teacher who told the student he could be arrested for saying something bad about obama? Lots more teachers like her than there are who know better.