We've had loitering munitions that choose their own target autonomously for a long time, for example anti-tank weapons that climb up after being released from a plane or helicopter then sit on a parachute until spotting one or more tanks and firing warheads at them.
The superficial new thing here is the exact quadcopter form factor, but the significance is the new price point. You bet the loitering anti-tank weapon costs a fortune. These drones are very cheap.
Of course, mines can be even cheaper, but you unwittingly engage them rather than them engaging you.
> but you unwittingly engage them rather than them engaging you.
Directional anti-tank mines are a thing: https://en.wikipedia.org/wiki/PARM_1_mine
I think autonomous drone mentioned in the article used some sort of "kill all targets" mode indiscriminently much like traditional munitions.
In the article there's no mention on the targeting works, self guided munitions have machines as targets, usually. A drone by itself might kill civilians and even allies if ot misidentifies a person or animal.
Anti ship missiles also need to search for targets once in the area
I think the difference between a targeting a specific piece of military hardware compared to training an AI model to target humans and infrastructure is quite different. This explains why drones that get misdirected will target oil infrastructure in friendly countries.