Yea, the aliens fighting against humans in F-16s on Earth? That's completely contrary to how everything works out in the books, and really undoes the sadness of the end of the book.
In the book, the humans were a fairly large galactic civilization already. The buggers were a neighboring civilization and on first contact attacked a human ship completely unprovoked, wiping out the entire crew, and triggering the war. From the buggers perspective, there are no individuals, only the collective mind of the swarm. By destroying that one ship, they were just trying to say, "Hey, this is our territory, please respect our borders." They had no idea about individuality, the sanctity of an individual life, or that the action would trigger a full on war between the two civilizations. The war was just a misunderstanding.
If in the movie, the first contact is the buggers trying to invade Earth and completely wipe out humans with their just present day technology, then that just turns the buggers into warmongering assholes that deserve to be wiped out, no misunderstanding at all.