You are making too many either/or black/white assumptions. Just because we have evidence (perhaps part of a craft) doesn’t mean we understand it.
Why inject such assumptions unless you are trying to remove objectivity?
This portion of a craft would have to have some unique properties to it, to state that it is not human made. Share what those properties are.
Again, I refuse to accept their statement on face value. There was a day when I would have, but that day passed many moons ago. 🙂