I agree this is a problem. The best reason I can come up with is “because it is fun/beautiful/interesting” (to some people).

But IMO that pushes you to making the curriculum more flexible and not forcing every student into the same sequence where math is the core IQ test for STEM. If a kid doesn’t find it interesting I struggle to justify forcing them.

Personally I also think trig and calculus are far inferior to statistics for most people. If you have an intuition for probability distributions, precision/recall, and a few other basic concepts, you’ll be guaranteed to apply them everywhere in your life.

Of course if you are interested in STEM then calculus must be available too, but it’s pretty specialized in practice.