I think that you have to focus on whether you have a human in the loop and can the human reliably interrupt an automated kill chain before there is a release of ordinance (much less fuzing)

If there's any point that a human cannot 'abort', then it needs to be classified as a WMD.

Out of human control I view swarm UCAVs as an unrecallable remote shotgun for the same reason as the article author, it's "inherently indiscriminate".