I am fine with the basics (e.g. classical vs rock/punk vs pop based on instruments) but there’s loads of other terms that aren’t very intuitive.
What is the difference between “alternate” rock and I guess “regular” rock? What is the difference between rock and punk? What is post-(insert subgenre here, like punk)? What is pop rock (the music subgenre, not the fizzy candy rocks), and how is it different from rock pop? What makes music “progressive”? What on earth are the “blues”? What is the difference between rock, metal, hard metal, heavy metal, etc. aside from an increasing level of angriness and decreasing level of clarity? etc etc
They tend to be distinct styles, similar to how bands within a genre can sound really different to each other. Now imagine that a couple of other bands says that one band’s style is the bee’s knees and start doing similar music.
It does get a bit too opaque and subtle at times, but I still think it’s usually helpful. e.g. “increasing level of angriness and decreasing level of clarity” is a big deal, many people don’t like listening to the extremely aggressive/unclear stuff and thus might say something like “I don’t like death metal, but power metal is great”. Even a Death Metal fan might think Grindcore is too much, etc.
And it’s pretty annoying when two things that should be different genres commonly get lumped together, like the early 2000s UK dubstep that was really bass-heavy, and Skrillex’ chaotic robot noises.