You may say that they ‘fear’ that their children are being groomed, but the meaning in that context isn’t fear. It’s more like see, realize, understand and are enraged. That’s why they stand and confront the people who are responsible for it.
Constitutionally, there is no restriction to public funding of religious entities. There has been much bastardization of a phrase from a letter. In our country’s early stages there was significant government funding of religious schools.
The performance of charter schools is easy to find, here’s one example:
“The researchers demonstrate that these learning gains were realized by tens of thousands of charter school students across the country, and progress was particularly strong among Blacks and Hispanics and those living in poverty. The study notes that these gains show that it is possible to achieve positive learning outcomes at scale and accelerate growth for students who have been inadequately served by traditional public school systems.”
https://www.hoover.org/research/charter-schools-new-evidence-student-success-matter-fact-national-charter-school-study-iii
They may not have been tested on their ability to condomize a cucumber, though.