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
Umbrella term is by definition something that acts as a general category, allowing for broader discussion before diving into the unique specifics of each sub-category - which is essentially what a “genre” is. The question was what do all the sub genres of music mean. My answer was that they’re specific labels which are useful in certain discussions/contexts (music criticism, academia, technical enthusiasts), but they don’t necessarily matter in day to day ordinary life, since the umbrella terms are more than enough.
You are answering a question no one is asking. OP specifically talking about what makes genres and sub-genres different. No one is confusing Muddy Waters with Britney Spears. Which is why they are labeled differently.