I think the "everyone hates BD because they win" argument, while correct for a small minority of fans, is vastly overstated. The average fan attends shows to be entertained, and will give it up for an entertaining show, regardless which corps presents it.
I love that BD has such talented members, I love BD for the high level of achievement the members attain every year. The shows are extremely well designed. But at the end of the day, the audience by-and-large does not reach the same level of excitement for the shows that they present. They do not produce an emotional response from most of the audience, the way corps like Phantom and Cadets do. It's kind of puzzling actually, to get to the end of a show that's designed so logically, and performed so incredibly well, and not have the urge to go crazy with excitement. But for a lot of people in the crowd, it just doesn't happen. And for the vast majority of those people, it's not because they have 14 championships.