Any black hole generator that doesn't itself become a black hole is essentially throwing part of itself in the black hole (Yay conservation laws!). You can replace the catapults with lasers or plasma guns or whatever.
Sure, but I think the original commentator was imaging a massive sphere that could emit such powerful and precise gravitational waves, that you could create more black holes as a result. My point was just that any mass capable of achieving that, even hypothetically, would have long since collapses into a black hole.
I take your point however, that you could coordinate in some way separated masses, but at some point you'd probably run into issues with the aforementioned galactic-scale of engineering.
