I don’t think it’s about drafting for need. Of course you draft for need. They’re not taking a QB, WR, or RB at #17, because they don’t need one.
It’s about not forcing your hand. At #17, what if the best defensive player on the board is inexplicably there, because six teams in the top 16 took an offensive tackle. It’s bad business to resign yourself to taking the 7th best tackle because you didn’t prepare for the possibility in free agency.