All of the decepticons were "killed". I realize you love the franchise more than me, and of course know more. But regardless of that you have to get past some of that shit and realize that in order for anything to ever be adapted into a movie changes must be made. Why was bumblebee not a beetle? And why were decepticons cars?
I can answer those questions for you without knowing everything about transformers. It makes for better chase scenes and cooler looking shit on screen.
I loved when Optimus would say "autobots, roll out"