True. Rock has more good singers than bad ones. But it doesn't seem to be a requirement. However, it is possible to have a good rock tune if the singer is not so hot. There is a lot of good punk with terrible singers IMHO.
Rap on the other hand seems to be “written” by a roomful of hyenas with typewriters
HA! Got me with that one.
A few bad ones..."The Boss" can't sing his way out of a wet paper bag, he just hollers.
Bob Dylan pretty much sucked, Grateful Dead, same thing. Judy Collins never saw a note she liked.
Neil Young was tonally accurate pretty much, kind of whiney, but I liked him (until he got political)