*Everyone*'s eyes deteriorate as they age, it's a fact of life - in which case new glasses fix that problem.
You don't need a degree to see that there is no reason beyond pickiness that people without perfect natural eyesight should not be able to become pilots - especially as, as you say, they often end up wearing them eventually anyway. Whereas, on the other hand, glasses/lenses have a far greater impact on an infantryman in the field - but that's allowed...bank balancing hmm.
Plus, eyesight deteriorating at a young age is usually an adolescent thing, and stops when you have reached adulthood (until the problem resurfaces in the mid-40s, as it does for everyone). They're excluding 20% of the demographic just with this one rule that will not in any way prevent the pilot from doing his/her job - in no other line of work, whether people's lives depend on it or not, would this be allowed.
It's very similar to the case where an otherwise fine candidate was turned away because he was too tall for fast jets, but not too tall for other aircraft. Where's the sense in that?
If it was such a problem, then, they would kick the pilots out whose eyesight deteriorates..but that's obviously not the case. They get their glasses and they get on with the job exactly as they did before. Not to mention that there is no evidence for modern laser surgery techniques causing any complications later in life.
Also an objection to such a rule has nothing to do with extroversion or military discipline.