But for the particles to get into the oil it has to get past the pistons and rings, so they have to be destroyed, not just scored. Certainly I would agree that the filings from the compressor housing could get into the cylinders and score the bores, but again getting into the oil is a different matter.
Another way for the particles to get into the oil is if the seal in the turbo was destroyed enough for them to enter that way.
While the Inconel of the turbine is considered a "ceramic" it's not like the vitreous porcelain you would find around the house that will shatter easily, but it is still brittle.