So why exactly are they going back to Lego Land instead of breaking this fodder giant's neck and actually going to Elbaf, the place they were excited to go to? Isn't the world on the brink of flooding, and they need to get to the One Piece ASAP? I suppose that ticking timebomb will only get relevant once Oda actually needs it.
I guess Nami forgot to use her supernatural navigator powers to identify the "Sleeping Mist Area" and do anything about it, as well as the Giant Pirates conveniently not telling them it exists (unless it's not a New World thing, but a power of some sorts).
Just don't think about it, plot needs to happen.