Grammy Awards Music Biz

That was the first year of the heavy metal/hard rock category, which is why it caused such a ruckus.  Prior to that year albums from those genres were just never nominated for anything.

I'm sure the real reasoning behind it went like this: "We will never, ever nominate heavy metal for anything. Crap, people keep complaining, what do to? Let's just create another category so these people will shut up. That way we don't pollute our other categories with this ilk."

S.D. wrote:

That was the first year of the heavy metal/hard rock category

And it was a combined award for heavy metal and hard rock, which often gets overlooked. So they weren't necessarily saying that Jethro Tull were metal, although it doesn't let them off the hook as it is still a stretch to call Crest of a Knave hard rock.