I agree, some pretty crappy design there, but I can also maybe see a reasonable counterpoint.
These weapons are not to be used law enforcement style where a quick draw may save your life. The hardened door is meant to slow the entry of the attackers and give the pilots time to respond, and the rules requires the firearm to be disabled anyway during trips out of the cockpit. Therefore I don't know if it is critical that the round be chambered until it is drawn. If a round is not chambered while the holster is in use, the lock design is moot.
I think you could argue reasonably well that the time required to rack the slide and chamber a round would have no measurable affect on the outcome of this particular type of conflict, but would increase the safety margin somewhat.
You could also argue that the moment that the door is opened to deliver coffee or allow a bathroom break is subject to the greatest risk of a rush attack, but I suspect if we tested that scenario, a proficient attacker(s) could disable the pilot with his own gun before he had time to recognize the threat. Much more likely that they would successfully defend an attempted breach of the door instead, and in that case time is on thier side.
We have all seen the accidental discharge videos from active LEO incidents (like the DEA in a class full of kids), so the risk vs reward in this case has to be studied.