User blog comment:Ygrain/ME sequel: what shall we do with the extinct races?/@comment-1786741-20121123181305/@comment-24174486-20121123181449

"Space magic" might make a little more sense once you take into consideration that Destroy is the only ending in which Shepard can survive.

The way I see it, Destroy targets synthetic systems—as the Reapers are partly-synthetic, this would disable them.