I don't see why computer games should not be allowed in the monastery. I guess with times, even monks have to "come out" and "see what the world is doing", so that in future when they come out to teach the lay people, they can relate and adapt to the constantly changing world.
It can also teach discipline to the monks, that when it comes to Dharma it is Dharma, and when they have their time off, they can do whatever they want. It is good for monks, young or old, to keep improving with skills and exposure, as they might not know when they would need to use it.