I would like for someone to explain to me why it is so common for modern pistols to not have a manual safety? Please, don’t insult my intelligence and explain that most every modern pistol that does not have a manual safety, does have a trigger safety. Though I understand the purpose of a trigger safety is to prevent the pistol from firing unless the trigger is pulled, I was under the impression that was already the case with a pistol—well, except maybe for the P320.
You can also save time by not explaining that with the lighter than double action pull you find with striker fired pistols, the trigger safety can help circumvent something other than your finger from pulling the trigger. We’ve had a mechanism to provide that same protection for more than 100 years and it’s called the manual thumb safety. If it is engaged you cannot pull the trigger even if you want to. Is a pistol with a passive trigger safety, safer than a pistol without one? Yes, but only if you keep your finger off the trigger.
You might also want to make the argument that the real “safety” is between your ears. I’ve said this in the past and it is a phrase that has been repeated by most every firearms instructor, gun writer, or even casual shooter. The problem is that the stuff between your ears is actually a very poor safety. History has proven its propensity to fail—fail when we are handling firearms, when we’re driving a car, and when we open our mouths. Yes, if you follow the guidance a trained and properly functioning brain can provide, it can help keep you safe. Humans sometimes ignore that guidance and move—or talk—faster than they can adhere to it.

Passive trigger safeties are now even included on bolt action rifles, but bolt action rifles with passive trigger safeties—Savage AccuTrigger and Mossberg LBA—still have manual safeties. In fact, manual safeties are a standard feature on rifles. Hell, we now even have manual safeties on lever action rifles, which already had a manual safety called a half-cock.
I like the idea of a manual safety on a gun because it serves as an ON/OFF switch, and humans are very accustomed to switches and the concept of turning things on and off. A manual safety lets you turn a gun on and off. Being able to turn a gun on and off is important, because humans often ignore the second rule of firearms safety, which is to never let the muzzle cover anything you are not willing to destroy.
The beautiful thing about this safety rule—the thing that makes it most important—is that if you follow this rule, you can violate one of, or all the other three rules, and the worst thing that will happen is that you will be embarrassed and possibly have an intense ringing in your ears. Accidental/negligent discharges happen all the time because humans are relying on that safety between their ears. In fact, it’s the failure of that safety between human ears that leads to one of the most frequent self-inflicted gunshot wounds, and that’s when a shooter fails to remove their finger from the trigger when they holster. That passive trigger safety won’t help you in that situation.

Could a manual safety prevent this type of unintended discharge from occurring? Yes and no. If you remember to engage the manual safety before you holster, it will prevent the pistol from firing even if you leave your finger on the trigger. However, if you forget—if that safety between your ears, fails, and you forget to engage the manual safety—it will not protect you at all.
Which is easier, remembering to turn your gun off when you are done shooting, or remembering to take your finger off the trigger? Beyond that, there have been instances where something gets inside the trigger guard when someone is holstering and it makes the pistol go bang. If a manual safety was engaged, it would not happen no matter where your trigger finger is.
Though I don’t carry inside the waistband in the appendix position—because I like to avoid breaking safety rule two—I cannot imagine how anyone would consider carrying a gun in that fashion unless it was equipped with an on-off switch…and even then, would you carry a rifle around—safety engaged—with it pointing at any part of you? (I can guarantee you this: even if you like pointing your pistol at your pecker, your buddy will not like it if you point it at any part of him.) If that safety between your ears fails you when you are holstering or drawing from that carry position, you may very well put a hole in your penis, blow your balls off, or allow a bullet to destroy your femoral artery. Though I have never experienced any of these things, I cannot see how they would be pleasant, and they might be something you cannot recover from—financially, or more importantly, emotionally and physically.

A friend who is a professional hunter never uses the manual safety on his bolt action rifle. Instead, he relies on a manual safety of another type. He carries his rifle with the bolt handle in the “up” position. I asked him why, and he said he does not trust mechanical safeties. But it is also perfectly clear he does not trust grey-matter safeties either, or he would just keep the bolt closed on a live cartridge in the chamber and head off across the bush veld with the manual safety off too.
Would you consider purchasing an AR15 that did not have a manual safety? Would you buy a bolt action rifle that did not have a manual safety? I doubt it, but there a lot of folks who are carrying a pistol that does not have a manual safety, and a lot of them are carrying it with the muzzle very close to their manhood. I know some will argue that revolvers do not have safeties, and that we’ve been carrying revolvers without manual safeties, for years. That’s true, but it takes a hell of a lot bigger brain fart to inadvertently pull a 10-pound trigger than it does one that requires half that effort or less.

The only two shotguns I own have manual safeties. Every rifle I own has either a manual safety or a half-cock (lever guns), and my primary carry guns have manual safeties. I have, and sometimes do, make exceptions in certain circumstances where I cannot effectively conceal one of my primary carry guns. But those exceptions are rare and I try to avoid them.
I like guns that come with an “on” and “off” switch, because to me, “on” and “off” switches just make sense. They make sense because I expect at some point I will do something that will not make sense. That thing between my ears has failed me in many ways, on multiple occasions, and I know it will let me down again. At some point it will fail you, too. I just hope that when it does, you’re obeying rule two or that you at least have your gun turned off.