I'm finding it very funny, because I though it was incredibly obvious on the movie, and nobody would ever disagree.

Indeed, the movie is way too busy, so it's easy to miss that there are no insects on space, or that the bugs weren't even aware they were been systematically attacked until "now". But it's one of those things that I expected to be completely obvious once pointed out. It's even more obvious than what you are narrating from the book, because on the movie Earth has been receiving those rocks for decades.

I imagine people missing the point is part of the point of it. It's like that gorilla video.