Those are the rules for the calc download section. The music section originally only allowed staff material. For some reasons the rule didn't get edited after the section was open to 1000 post members.
Also IMHO it's better to limit it to 1000 post members so people won't sign up only to post their 50 songs in the downloads section, than forcing Netham45 to pay extra hosting fees to increase his diskspace to 10000 terabytes.
TIMGUL website is about 4 GB of music downloads because people only go there to upload their stuff.