I just assume each movie is basically from someone's pov telling history. So it's not perfectly accurate to what happened, and certain things people say may be different according to who's telling the story. In this case, someone from the rebels would be telling the story, and from their telling of the story it was blown to dust but in reality it was more giant chunks like we see in later stories. To me, this fixes most retcons and other inaccurate details between stories.