I think the more pressing matter is what will Homeworld do when they find out that Steven's a hybrid considering what they did when the CGs started using different gem fusions but we can ask that question later. Anyways the Diamonds already know, 99 percent of the other gems won't care that their leaders did this, and when the Diamonds find out that the Cluster is bubbled they'll probably realize that the CG are somehow alive and I'll get to yell, "The Diamonds are coming! The Diamonds are coming!"
Let's be honest, the Gems had no word for 'atrocity' until Rose came along. The Earth is not nearly the first planet they've attempted to destroy; and it's highly likely their entire society is built upon the unbridled genocide of every other form of life in the known universe.
So your saying that homewolrd is a existential threat to all organic life