He's definitely talking about the "you HAVE to finish calculus in high school" track as representing "rigor" and some kind of badge of smartness/worthiness in high school students. That's not at all the same thing as a student who legitimately takes a very rigorous approach to mathematics but simply does it FASTER than most learners can. Those students are somewhat rare. That's what he's getting at; undermining the prestige of "advanced in mathematics" for its own sake, and a return to rigorous learning-- for ITS own sake.
Many scientists, engineers, and economists will use calculus and other math as a tool. I wonder how much rigor they need. I don't see how a year of geometry with proofs helped me in my academic or working career. A benefit of acceleration through calculus is that it enables you to study physics, statistics, economics, and other subjects at a higher level.
I'll speak to economics. All that's really needed to cover graduate material is the first year university series of calculus and linear algebra for math majors, with some second year stats to cover econometrics. To get published in AER or Econometrica, it's helpfully to have more econometrics.
I studied in Canada. My profs who had taught at Harvard and Princeton used their graduate textbooks for my upper year classes because, apparently, those universities' students didn't have the requisite math background to do the graduate work yet.
My husband stopped his studies in physics and math in high school. Had he had more rigorous treatment of math before university, he says would have gone into physics and not law/finance.
