I'm not really sure if thats completely true. Taking the BPA is much easier said than done. Everyone says it, but it takes some guts to stick to it. There is a lot of pressure to win now, so that probably leads to some people factoring in need more than others. Probably what separates good GMs from the not so good ones.
Team's draft boards are listed vertically and horizontally, meaning players with similar grades are grouped together and listed horizontally. A good GM who sticks to his guns and truly believes in the BPA philosophy should only factor in need when picking between players with similar grades.
Just like with any rule, there are probably a few exceptions. We probably wouldn't take a QB in the first round, but for the most part, a confident GM won't reach for need because he knows how to fill the gaps with cheap talent. THAT is what makes a good GM.