I went to public HS in the US, and the math education there was terrible and completely sub-standard. The science was about average. Now, the school wasn't all bad. The humanities (English, Latin, German, French, Spanish, History) were all of very high quality. I had to do remedial math work before going to college, but had a perfect score on my verbal SAT. I've often wondered why that happened. The only reason I can come up with is that it's harder to get qualified and excellent math educators because those people end up making more money elsewhere.

There is a relevance problem, yeah. I personally was motivated to really learn calc in 1st year college, mainly by physics classes. I wasn't a physics major, but I found the freshman physics class really interesting. In particular I found it interesting that via this tool, calculus, you could actually re-derive the entirety of elementary physics (stuff like dist = v0 t + (a t^2)/2), and much more, via a procedure with more internal logic and less arbitrary memorization. It almost felt like a successful good-cop/bad-cop setup: bad-cop high school made me memorize a bunch of bullshit special-case formulas, and then good-cop college explained to me that you could just do calculus to derive the answer.

I could certainly see how those motivators wouldn't apply to all students, though. Honestly they applied to me mostly out of personal, side-project-esque interest. In CS I tend to use statistics and discrete math a lot more than calculus, though calculus comes up occasionally.

i hated math when i entered college despite having passed the AP calc exam in high school. i didn't see the point and couldn't understand why i was learning about functions. i had no idea how to even think about the subject beyond what i had been told to memorize.

the second semester of my sophomore year i decided that my interest in computers and desire to have a job lead to me changing my major from psychology to computer science. i signed up for calc II as my first college math class and felt exactly like you did, getting an A+ despite not having taken math for almost 2 years.

i hated high school math because it felt like pointless memorizing of stupid facts. i loved college math because it was about describing and reasoning about these conceptual objects and i didn't have to memorize a thing if i could just remember how to derive it. they explain how to think about these objects, and once i understand the framework behind the subject i enjoyed it much much more.

the fact they were reasoning, explaining/proving why the math worked, and presenting the logic behind their thinking was enough to make me love it. i went dual math/cs and eventually got a MS in pure math.

Fun fact: at at least one college, the psych department has too many students. They knew they would get into trouble with the dean if they started failing them, and there was no mechanism to impose a cap.

So they added a calculus requirement to cut the numbers.

That's a horrible way to look at a college experience. As a student you're paying good money to get an education. If you treat it as a monetary transaction in exchange for a credential then you are unlikely to get your money's worth.