I didn't say I agree with the theory, I said it brings together some interesting points.
It is obvious that the diable jambe is not the result of any modification of the Judge. That would be a complete rubbish script that I doubt Oda would do;
But for sure there are some tips that connect Sanji to the Lunar race, like the fareshadowings, the mention of Queen and the parallels of Sanji and his family with sky and birds
Since Sanji's theory of ''cosmic powers'', which was completely popular due to the plethora of hints that made a lot of sense, to the fact that Sanji has a lot of things that connect him with cosmo, I've always thought there's something about it, so the lunar race will fit like a glove here