1: Expired personal armours of the aramid variety show operational status after testing. It's just a "cover our ass" system. The EX date is the maximum that they can guarantee full operational state under standard wear and tear iirc.
2: Cost of dead operative is high. If memory serves, average US Army soldier is 300k for basic training, not including specializations and such. As such, by logic, it makes good fiscal and moral sense to ensure operative returns whole.
3: Issue with armor manufacture is just typical. No producer will make perfect record, even most sterling of silver will have a small blemish. It happens. Response is how you judge.
4: You would be surprised. German, Israeli, British, and Russian industry of protective gear is quite excellent. However, in some cases like India and their Alibaba Armour, this is true. Quite frankly, their items seem atrociously made.
Edit: Also, the SLAM... Ah yes, I too like slowly turning my barrel into a krummlauf.