You know, then maybe don't sell the pattern if you don't want someone making it?
Does that apply to music as well? "If you don't want someone using your song, don't sell the sheet music." But that doesn't apply, because selling the sheet music doesn't give the buyer the rights to perform the song in any and all circumstances. Musicians can choose how to license their song. They can sell the sheet music for people to play in their own home, but not use the song on the soundtrack of a motion picture.
How is the pattern of notes showing how to construct a song different from a pattern showing how to make art out of crochet?
Is a pattern. In fact, it's the same basic start of a pattern most crochetters will run into when making any rounded shape such as a ball, egg, or beanie. It's copyrightable. Maybe not those 4 rows, mind you, but the pattern in its entirety.
No, it probably isn't copyrightable. You can't copyright the design of a utility item. Hats, blankets, socks, etc. You can't copyright how to construct a basic utility item. You can't copyright how to make a blanket. You can copyright a quilt that looks like an original artwork when pieced together. Both the pattern and the resulting art could be copywritten, and presumably the rights holder should have just as much control over what could be produced from the pattern as someone licensing rights to a photograph or clip art.
Utility designs aren't copyright, they're patents. What should be copyrightable is artistic design. A pattern that makes art, and you absolutely can copyright that, and someone copying the artwork is breaking copyright, no matter what medium they copy it in. I can't paint a picture of someone else's photograph and then sell it without being in potential violation of copyright. If someone has a pattern for a hat, unless they've got a novel way for a hat to function, they can't patent or copyright that. If someone has a pattern for a
unique art design for a hat, something that makes it a unique artistic work, and not just a utility item, then I think that should be respected.
Something like this is an artistic work, and shoudn't just be copied without respecting the original designer:
Something like the beanie you posted is a utility item, and that pattern can't be copyrighted. Maybe a specific color pattern could, but not the basic shape of a beanie.