Why is "It's something to do" apparently a valid defense?

[RiceisNice]

They weren't referred to as Zodiac weapons originally--the first mention of them as Zodiac weapons wasn't until 2.2, when they added the Atma/Animus stages. Up until 2.2, they were referred to as Relics (the quest title was A Relic Reborn).

And I did find one of the interviews I was thinking of, but it looks like I edited it in while you were writing your post. The gist is that Yoshi says they added the Zodiac weapon questline specifically to address player feedback desiring another way to acquire weapons. He doesn't say that they're changing their future plans regarding Zodiac weapons--he says that's why they added them in the first place.

Your quest log categorized it as Zodiac Quests as a subcatagory in side quests after it was completed. Unless it was changed going into 2.2 (which isn't documented, and if [in]consistency is their thing, it might as well [not] have.