Maybe because insect wing, gnat wing and puk wing is also under Clothcraft? The consistency helps sellers easily figure out where they are under the AH to figure out an appropriate price. And people who pick one up to sell them isn't necessarily going to know what craft it is or isn't used for.
Besides, SE could add a ladybug fletchings recipe in the future.
Lyonheart of Lakshmi
lvl 99 NIN WAR BST THF BLM SCH WHM
1/467 on signed HQ Weskit!!!