"Slipknot is none of these, and much more of a pop/heavy rock act if only because Corey Taylor can actually sing at all. True "cookie monsters" can't."
Ok, I have to learn to live with the fact that Slipknot are then a Patridge Family with horror film masks of sorts!
I actually like Taylor's singing when he does it in his day job, but even more with Stone Sour.
I didn't know that the "growl" ruled out singing per se - some people change over time, the Nightwish leader/bassist used to be a severe growler intiailly and only hints at it today. To me it's sort of the other side of the spectrum to what Kind Diamond did.
I never got him in the 80ies, but recently took the brave step of buying Abigail and listening to it all the way through in the car too. Probably won't repeat that exercise too often though! Thinking about it - when he did not screech, he growled too, so he must have been among the first growlers together with those lovely harmony singers from Venom of course!
And I guess Lemmy was halfway there with his singing style in Motörhead (he was a lot more melodic both vocally and on the bass in Hawkwind daze). When I first saw Motörhead around 1978 or so, I did not qualify what Lemmy did as "singing" at all.