The tread was initially indeed about takeoff terrain clearance.
An EO for an approach requires a different set of performance criteria, notable the Missed Approach Climb Gradient requirement and the Approach Climb Gradient requirement. Both are described in subsequent areas of legislation (JAA/FAA) regarding aircraft performance and can be found/quoted here if needed by others.
In simple terms, an airport may instruct aircraft outside a MAP to execute the missed approach procedure if from the MAP any aircraft requires the minimum legal gradients required to fly the defined missed approach procedure, as these are defined and each aircraft is certified to be able to achieve them, this would be safest option in general.
Think of the alternative, an aircraft proceeds beyond the MAP and then executes a missed approach for whichever reason and cannot achieve terrain clearance due to being incapable to achieve the required climb gradients...
Pilots are to ensure that missed approach climb gradients and approach climb gradients can be met before proceeding on an approach.
Some airport define different minima based on an aircraft's achievable climb gradient, always measured from the MAP, thus achieving the use of lower operational minima if you can achieve e.g. 4.0% instead of 2.5%, raising your chances of completing a successful approach, especially in non CAVOK conditions.
This can be a very useful feature if the aircraft on the actual flight is light enough and thus be able to use lower operational minima.