Teachers' unions hate charter schools. But if charter schools perform badly, parents can walk away. Without competition from charter schools, it's harder for parents to take their kids elsewhere.
This is right out of Hirschman's Exit, Voice, and Loyalty: voice/complaining, isn't always enough to effect positive change in an organization, so it's good to have the exit option. Businesses, churches, even colleges do not have a captive audience, so they have to be wary of losing clientele if they don't listen to their voices.
Public K-12 teachers' unions want to deny patents (and their children) that exit option, which means they won't have to listen to their voices as diligently.
This will hurt minorities the worst. The wealthy get private education. They've exited without ever entering the public school system. The reasonably well-to-do may stretch to exit, but if not, their voice is more likely to be heard. Those whose voices will be, because they always are, attended to the least, will be the poor, minorities, and especially poor minorities.
Tell me if you don't think that's true.
So here in Buffalo we have a charter school that was doing a great job teaching minority kids, and they voted to shut it down. Not the parents; they could have walked away if they were unhappy. Legislators; and teachers' unions swing some weight in legislatures.
Fortunately that closure was reversed. But why did it happen?
Because unions care more about their power than their product.
The New York State Board of Regents voted to close one of the highest performing schools in Buffalo.
— Corey A. DeAngelis (@DeAngelisCorey) June 9, 2020
94% graduation rate
#4 in math
#6 in science
90% of the students are low-income
They just reversed that decision.