Any holding point where a through taxiway route passes behind doesn't necessarily mean that their is sufficient clearance between the aircraft holding and the one taxiing behind. Several collisions at different airports have occurred in the past as a result of misjudgement in this scenario.
Never assume that an aircraft will hold as near to the holding point as possible therefore ATC should never assume that there is sufficient clearance to pass an aircraft behind. In most cases the tower is so far away it is difficult to assess what clearance is available and it is at pilot's discretion.