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
I don’t think anyone understands ALL of them.
As you become familiar with a certain style, you notice differences between them. The deeper you dive and the more you listen to, the finer details you can recognize.
I could probably name at least 25 different genres of rock, and explain how they are different, but styles I’m not familiar with, I can usually only recognize the broadest category. Bluegrass all sounds like bluegrass to me, but an expert could identify 25 different subgenres of it.