as a kid who attended middle and high school at a private evangelical school, I can 100% agree. it was a terrible environment
among the many issues with the school, a common issue we had was kicking out queer students and/or outing them to their parents. we had a pretty robust exchange student program, and in my junior year we had one study abroad kid who was very excited to be away from her parents and able to explore her queerness like she had not been able to do while under their roof. she confided in one teacher and a couple of students about her identity, which made its way up to school management. she was immediately removed from classes and sent back to china, with a letter to her parents outing her. lots of queer students did "lavender dating" to get some heat off them if they were suspected of being queer
our health science teacher in high school constantly humiliated our trans guy classmate by having him always be the example "woman" when comparing physical differences between men and women
1/4 of our in-class time was spent on religious studies or attending a mandatory chapel service (basically a mini evangelical church service, with church rock band and all)
I have a vivid memory of my earth science course in 8th grade, when we were going over the fossils unit. my teacher (a young earth creationist, as most faculty were) quickly skimmed over the section, as fast as possible bevause she didnt want any questions or to expose kids to actual science for too long, and wrapped the lesson up by saying that there's not enough time in the "6000 yr history of the earth" for anything to fossilize, so fossils are all fake. after the lesson I went up to her and said "okay so if all fossils are fake, and they're discovered all over the world, how'd they end up there?" and she very solemnly said "satan put them there"
so please don't send your kids to private religious institutions esp if they don't believe in your religion. hell, even if they do believe in it, the education quality never matches the price tag of sending your kid there. and the trauma of being queer in that environment and the religious trauma stick with a person well past graduation