Sorry for my ignorance, but why should anyone in the pool forget about it and move on? It sounds like DN has stated that when the company starts recruiting again then they will start taking people from the pool - and why wouldn't they? The hold pool consists of people who have passed their very thorough selection process and therefore people who they deem to be suitable to join the company.
I think it's quite simple - Tfly have not recruited for about a year now, so nobody from the pool has been taken. When they do start recruiting again then they will start taking people from the pool. One of the main reasons they haven't been recruiting for a while is because they have gone through a huge merger.