A lot of the same people did win, but a lot of the same people were also nominated. You can't blame the people who won because, as Julilly said, it's the readers who do the nominating and the voting. Sure, you can vote for yourself, but only once, and you're not allowed to nominate yourself, nor is an author/story allowed to win the same award more than once. So none of these same people have won in the same category for the same story before.
Unfortunately, there just isn't as much variety in the fandom as there used to be. There are fewer authors still writing and not as many options to choose from in certain genres, which narrows the playing field. I really had a hard time nominating something in every category this year because I only wanted to nominate well-written, finished, recent stories by authors who are currently writing - I felt it would be more meaningful than nominating old favorites by authors who are unreachable and couldn't care less about BSB fanfic anymore. But that definitely limited my choices.
In the end, it all comes down to the opinions of those who actually took the time to nominate and vote. If the awards had been judged, it would have been down to the opinion of a few judges. Either way, people with differing opinions would probably complain. It's impossible to please everyone, but the drama takes the fun out of these things.