What Winter Born said there, in the midst of the quote.
Kind of repeating here, but...
-Ships don't leave remains, so there's nothing to rebuild from.
-Only turrets and some other immobile defenses can be rebuilt.
-Clean-up drones are only good for clearing minefields at this time.
-If you want to capture enemy ships, use ships that have the ability to reclaim, such as parasites or leech starships, then repair the captured ships with a Mobile Repair Station (aka MRS).
The remains rebuilders are extremely helpful simply by rebuilding your own defenses anyways. As for ships... try to keep as many of them alive as you can when you engage in battle. MRS or two helps a ton there. You're always bound to lose some ships though, and rebuilding them from your spacedock is pretty trivial.