Invading Klendathu because of Bug meteor, False Flag Operation
It's because they wanted the brain bug for its knowledge. It was a false flag operation. Think the middle east is about "bringing democracy" or "stabilizing" it? Or to stop terrorism for that matter? Nope.
Notice how we never actually see any scenes with a meteor hitting the earth we just see them talk about it in a propaganda film. think about it, how ridiculous does it sound that the bugs would shoot plasma at the asteroid belt in such a way that it would send a meteor on a direct path to Earth? Now compare that with some of the farfetched facts about 9/11? (Jet fuel melting steel beams, Building 7, all the unanswered questions etc.) and you'll see that the film is a bit ahead of its time, or at least 4 years ahead of its time.
Only people with money say that money doesn't matter.