Even judging the movie's version of events, poster is wrong. What happened is the Rodger Young was on a patrol late at night when they suddenly detect a massive asteroid coming at them. Xander reports to the captain that it came from the Arachnid Quarantine Zone and a near collision destroyed their communications array, so they couldn't warn Earth. Xander is not providing propaganda to the captain in that scene and we never actually see anyone tow the asteroid or have the Rodger Young be in on the conspiracy, which is how you show a false flag attack in a movie. The most concession I can give is that there were two asteroids, one near the AQZ and another near Earth and it was all a coincidence, but again, that is not the intention of the film because of how the movie is edited.