Your experience is very different to mine. I went to high school in the 90s. Even back then, both JV and varsity were cut teams for most sports. Some sports were popular enough that they had no-cut teams for underclass kids. But that cost money for extra coaches, equipment, gym time, travel, etc… I was able to play basketball on the freshman and sophomore teams, but I was never good enough to make JV, let alone varsity. Now my kids are in high school and it is even more competitive, because the schools in our area have more students and less money per student for sports. My son tried out for freshman basketball. There were 60 kids trying out for 10 spots. He didn’t make the cut. Only kids who had already been playing on district select teams for years did.
I want to be clear: I don’t think it’s fair to ban trans kids from playing sports on any team. But I also don’t think we can expect people to just get over it. In their minds, at least, there’s too much at stake.