Yes the M9 has a safety and a decocker - so it has some redundancies and is a pretty safe pistol in that respect. The predecessor M-1911A1 also had a standard safety and a grip safety - you had to be hold it, depressing the grip safety for it to fire.
I don’t know what capacity you were in the military, but if you were on an actual armed patrol I imagine you had it loaded and on safe. I imagine too the MPs carried loaded and on safe.
I know carrying loaded is SOP for cops. Though they keep them holstered and generally in retention holsters. One can carry safely in holsters and like I said millions of people do every day now. And while a lack of a safety on Glocks seems odd, since the late 1800s with revolvers they were carrying loaded with no safeties. Though there was some getting used to the new Glocks and new safety procedures for carrying them. You can look up “Glock leg” to see that there were fails in that area and it is why NYC has their Glocks with extra heavy triggers (so heavy they are hard to shoot with out pulling the shot.) Personally I weigh risk likelihoods, and I figure I am more likely to have a negligent or accidental discharge vs need to use one for defense. Thus if I were to carry I would prefer a mechanical safety.
SOME have a mechanical safety in the trigger, but that isn’t to prevent accidental pulls, per se. Glocks and most (all?) striker fired guns have a metal bar that prevents the striker from moving forward enough to hit primer. This has to be moved out of the way and does so as the trigger is pulled. The trigger is raising that bar, cocks the striker, and releases it at the end of the pull. The point of the little “safety” lever on the trigger is that if you dropped the gun, and it landed with enough force that the trigger might move enough to fire the gun, it couldn’t actually, because the little safety on the trigger wasn’t actually depressed. I don’t know if this is technically called a safety or not - I don’t own Glock. I guess we could google a parts diagram.
That is the traditional idea of a “safety”. There are also internal parts to make a gun “more safe” in that it won’t fire when it isn’t supposed to.
Unfortunately, one of the most common causes for accidental death is either assumptions of an empty chamber, or a failure to properly clear the chamber. So in that respect you’re right - but in those cases that was their intent, they failed. In some “knew it was loaded” accidents, yes you’re right. It sort of depends on the situation.
Everything else is conjecture. I suppose in your mind you may be thinking someone pulled the trigger to murder someone, or themselves, and glad it didn’t go “bang” - to be able to “take it back”. Which is a nice idea, but probably not likely in most cases.
No worries.
Well - that IS true. Though there are “safer” designs than others - just like anything. One can have degrees of safety and still have it be over all “safe”. In this case it is less the tool failing to be safe, but the “tool” failing to be safe.