It helps to define "need" in a sense here, as there's "we need a DT" and there's " we need a DT that can play X technique." You can panic and pick a player based on the first that really doesn't fit the second. You also talk as if a team only ever has one "need," and that, I think is what BB is kinda contradicting. He's saying that you shouldn't panic and pick the next best player (regardless of how they'd fit at your scheme) at your "biggest need area" if the one you wanted is gone. Don't vapor lock on a position and forget the role in filling it. For example, LT might be considered a big need position for the Bills. D'Brick was probably high on the Bills' charts. But because he was gone, you don't grab Justice just because OT was your big need position and he's the next best OT. If he's the next highest player on your board and his techniques/style/skill fit what you're looking for, then yeah. But then you might have him ranked above D'Brick anyway. If he's not the role-player you are looking for, you look at other roles and how other players suit them....
Still struggling with a way to explain it. I do think I grok what he's saying, just having trouble explaining it in another way....