It always seemed strange to me from lesson One, controlling speed with attitude and rate of descent with power.
Now, with more than a few thousand hours behind me back, then I know exactly how it's done; thrust controls speed (and has a secondary effect on rate of descent) and pitch controls rate of descent (with a secondary effect on speed.)
Why is it taught differently at a basic level, because in the grand energy-equation we dance our lives around in, it is far easier long-term to have the power-speed pitch-ROD couple in your head than the one that is taught in basic training (privately, I mean: I was taught both ways, and the sponsored scheme taught me pitch-ROD from day one, all ex-mil instructors.)
It may be easier to teach one way than the other, but once one moves on to larger aircraft, then the mindset is forced to move by the very nature of their inherent aerodynamics, something that is worked-around on light aircraft, allowing for this debate.
Despite the fact that I am today flying a neutral-stability aircraft with autothrust speed control, the rules are still the same.. only difference is that I have a few ounces more capacity to look out the window.