You guys also seem to be ignoring the second part of what I said. Its the easiest way to lose a locker room.
There's a bunch of vets on that team. If they feel for one minute untested rookies are getting minutes over them undeservedly and start talking amongst each other, you could lose the locker room.
Once that happens a team and coach is doomed. Changes have to occur to attempt to lure potential future free agents because word of what the coach is doing will get around the league quick making Boston an undesirable place for vets.
Doc was hated by many around here but is one of the most respected coaches in the league, especially amongst veterans. Why? Because he develops his young players the right way and makes them earn their time over vets.
Veteran players respect that type of atmosphere knowing that as long as they play their game, they won't be sitting because management wants to develop their young through a baptism by fire concept costing them playing time.