Yup, that's my guess. That would neatly tie into the sheer unrivalled hatred CDs display towards the clan. CDs reject their existence so thoroughly because the past of Davies reveals that celestial scum were just usurpers of the OG royal lineage. And "gods" surely loathe being reminded of their faux nature. They want to bury the truth that spits in the face of their whole mythos that they've been building-up over the last 800 years.
Though I feel like Davy D. Jones will be revealed to be quite a fiendish fellow himself. There ought to have been some legitimate reason for the 20 kings to rebel, Vegaskunk lampshades this while going "blah blah, it's unclear who was really on the right / wrong side so I won't pass judgment, blah blah".
If I were to take a guess, I'd say that the original version of the Davy Back fight wasn't really fought between pirate crews at all. It's more likely that Davy D. Jones used it as a way to expand not some pirate crew (if he really was a king he probably wasn't really a pirate in the traditional sense, that's Joyboy's whole schtick), but the Ancient Kingdom itself. Wholeheartedly believing in the "might makes right" ideology, Jones probably challenged the strongest warrior-representatives of some yet-to-be-seized nations. If they won (which never happened, Jones was just that guy), they'd be allowed to maintain their freedom. If not, they'd become part of the AK by force. Basically, it would be an echo of Kaido's mentality, just executed in a grander, non-crappy way.
It would only be later, when the Davies are overthrown, persecuted and forced to become a part of the criminal underworld (aka heavily dabbling in pirate affairs) that the Davy Back fight tradition would be repurposed, altered to fit the circumstances of the harsh times.
I originally wanted to make this into a whole-ass thread of its own, but I guess this is as good an opportunity as any to write down the most substantial stuff.
