But Oasis is Brit Pop, it may come under rock but its easy to separate the different types by singling it out
Calling Oasis and Slayer both rock would suggest that there similar which they aren't
Fine fine, bad comparison, but there's still many more. The Clash, My Chemical Romance, System Of A Down, Animal Collective, Lightning Bolt, Led Zeppelin
all generally labeled rock but all have completely different sound, i think all the different tags are fine
The tags all tend to give us an idea as to the style of music involved, so as such are a good thing. The only time it's a bad thing is when it's used as a means of exclusion of people from various parts of society!!
BTW, do you realise that all the bands you named get a different tag??
If you don't have sub-genres to lable a type of music .. people who never listen to the style of music you listen to .. will never have a clue wtf you're talking about otherwise.
There are different genre's and different sub-genres .. so that people don't spend hours sorting through cd's they'd otherwise never pick up. lol