The fluff isn't meant to explore the length and breadth of the universe. That's for the Beyond EVA expansion or whatever it's going to be called. This is the core book, and is about one core campaign. In the space I had to work in there was enough room to either provide enough character work to demonstrate one example of how a general suite of characters and NPCs could be depicted, or a bunch of quotes that build on the fluff but don't actually provide any useful dimension.
Simply put, if you care enough about building your game's characters that this annoys you, you care enough that you don't need me to hold your hand building them. This is a core book, so it has to cater for the players with the least experience first. The expansions will have more characters, because they're meant for people who want to work outside the scope of events in the main storyline. I could have gone with canon characters and made things even simpler, but that comes at the cost of encouraging newer players to assume that they have to play canon characters only.
If it bothers you that much, why don't you contribute? If I'm doing most of the fluff myself, surprise surprise, most of the fluff ends up the way I think it should be done. Is that in any way unexpected?