As one of the earliest promoters and adopters of the bow_* tag, primarily the bow_panties tag, the idea to me at least was to emphasize that these were the iconic panties with the bow right in the front, and not just panties with a bow anywhere else like on the sides or back. The same with bow_bra, which match the bow panties with its iconic bow in the front, and not necessarily anywhere else. Since the bow panties and bow bra tags reached such high post counts early on, the bow_* language kind of bled into everything else with a bow attachment.
Admittedly, the bow_skirt has kind of bothered me as well, because having a bow right in the front is not really a thing as much or as iconic as the bow bra or bow panties, so using skirt_bow to match the existing dress_bow made a lot more sense.
For myself at least, I'd like to keep the bow_panties and bow_panties tags, or at least have something else to replace them, just because of what I already mentioned; namely the iconic look of those that have that bow right in the front. For the other tags, I'm not really as committed and would be fine with the other proposed aliases.