Roary.....that's exactly what Lindelof was saying....Prometheus is a true prequel in his eyes, taking place in the same universe but following a different narrative the previously established. I don't understand why this isn't clear to you?
There are two kinds of fanboy.
1. The Unaware Fanboy : it doesn't matter what it is, if it's related to his favorite film he's there. It could be the dumbest story ever written, but he or she doesn't care, anything they can do to add another dimension to their favorite film/book/comic/tv show, they'll lap it up. This kind of fanboy has very little discernment, any shlock thrown their way they're there, front row every time.
2. The Discerning Fanboy : committed to the integrity of the story presented, hopes that any furthering of the original keeps the same scope and integrity. The discerning fanboy defends to the last the original tale, the way it's told and how it can be developed to keep the essence true to it's core.
I believe based on his I interviews, Damon Lindelof is The Discerning Fanboy.