Yes & no....
That's true to a point but a new gun owner or sworn LE officer can train to carry larger caliber sidearms.
The large metro sheriff's office in my area has approx 1200 sworn deputies.
They have issued the factory stock Glock 21 .45acp since 2002. Some detectives & undercover deputies carry Glock 22s, 19, 36s, 30s, 26s, etc but none use small calibers(.25acp, .380acp, .22LR, etc).
Marksmanship is a skill & can be learned using proper methods.