@MoistDickExcel I think its saying that since rock creatures exist as a fallback for carbon based life in case they are wiped out, that their lives kind of suck as the lesser of the two species. And that the real benefit of being a rock human is that they receive blessings from the earth, places that they can call their true home (devils palm, the ground in Morioh), and that they are blessed with powers (their own rock powers and their stands).
So since rock humans stay in their own places (like devils palm and Morioh) and human migration shows that humans and rock humans don't have any really reason to gather in one place, and they can live their own separate lives.
Then it shows the steel ball run (that takes place partially in the devils palm), showing that in recent history humans are finally beginning to interact with rock humans and that is causing conflict between the two species. Humans are also taking the blessed powers that belong to the rock humans ((
stand arrows and stone mask are examples of powers that belong to the rock humans that the humans are taking(used as a parallel Dio isn't part of this SBRverse), and also humans like Funny Valentine can receive stands from devils palm which is a place meant only for rock humans)).
Josefumi, Kira, and the walleyes are shown as the primary source that proves that humans messing with what belongs to rock humans causes conflict
Lucy is just recognizing that the fates of rock humans and humans are now converging in Morioh-cho.
After the Lucy Steel dialogue, the flashback is about Rai's dads funeral, because by owning that pear orchard he was interfering with the HD's master plan for the rock humans to rise up. (The HD states that humans are not allowed to possess anything belonging to rock humans whether it be a pear orchard or a new rokakaka. on the last page of the chapter).
So overall I think its saying that recently humans are moving into rock human territory, stealing their blessed powers, and that is what caused rock humans to start planning to become more than backups for carbon based life but to become the superior lifeforms (supported by what Urban Guerilla says to Rai during the mountain fight), both species need the fruit for their plans, leading into the conflicts between the species that we see in JoJolion.
Idk why Lucy Steel is in Morioh, maybe she knows that when Johnny brought the corpse the land would still be affected even though the corpse was brought back to the USA and shes investigating, I still don't know what her motivation to join the SWF would be though...