Police and witnesses maybe can’t hear arrows released from bows, or crossbows either. They can’t hear knives, swords, hammers, pickaxes, hatchets,
Guns are used far more often to murder people than any of the silent weapons you mentioned. However, out of countless murders involving guns, only a miniscule number such as one or two in an entire year, a small fraction of one percent, involve using a suppressor on the gun. Most murders involving a firearm are cases where the killer doesn’t care if the gunshot is loud and heard. The killer is long gone from the scene when the cops show up.