https://www.quora.com/When-did-LEGO-set-start-containing-con...
The introduction of weapons was gradual, and except for Batman, they are either historical or futuristic.
From my observations as a foreigner in Denmark, historical or fantasy weapons like swords, spears, shields, clubs acceptable and common. A 6 year old might have a wooden one, and be seen anywhere in the city. A 16 year old might have a foam and fibreglass one, and be seen LARPing in the woods at the weekend. A gun that isn't clearly a water pistol is a rare sight.
Even though Lego sets do sometimes include weapons, even very gun-like weapons, to me there is still a pretty clear line Lego draws. Their City sets don’t include guns and guns are the exception, not the rule, otherwise.
Look at Lego’s competitors if you want to get an idea of what Lego could be doing. Obviously those are looking for their niche, so that’s to be expected. They have modern and 20th century military equipment sets and I could never imagine Lego releasing sets like that.
That line got me thinking. I think you are right and I've never seen a police minifig with a weapon.
Typical police equipment are handcuffs, megaphones, walkie-talkies, traffic paddles and coffee cups. The criminals might carry gold, banknotes, dynamite or crowbars and other tools.
The most gun-like thing in current sets is the huge net shooter (larger than a minifig and not portable at all) that really isn’t very gun-like at all.
Not even the minifig prints include suggestions of guns.
0. https://www.amazon.com/PLAYMOBIL%C2%AE-6872-Police-Command-C...
Admittedly a revolver and not a semi-auto, and I don't know if it's from a current or recently discontinued set. But it's definitely from a modern set.
edit: link to the specific piece: https://www.bricklink.com/v2/catalog/catalogitem.page?P=1356...
The BrickLink page lists the revolver as part of a bunch of western and cavalry sets, that is, historical sets. Click "Item Appears In: 7 Sets" to the right.