You can imagine the following perspective: - Most people don't need to learn calculus at all, and it's fine if the few weird students who do start when they get to college (maybe the advanced students can learn single-variable calculus in high school). - For pure signaling reasons, taking calculus in high school has become very important for college admissions. - In order to take calculus in high school, you need to…
I definitely think we should teach more advanced math (and other) courses, but that particular way of doing it is just not very good - plenty of people who probably could have managed Calc just fine didn't get to take it, due to choices made for them years past probably by parents who didn't understand the significance. The structure and order of classes needs to be redone, which is hard.
I will say though I find it funny how much people are coming to Calc's defense. I'm in software development and it's a pretty common joke how virtually inapplicable calc is to us. I'm still happy I learned it but for software development it's definitely less useful than the other advanced math you'll learn.