It's pretty much a lobotomy on a planetary scale.
the preferred term is "cuck ray"
If it was a hostile species why do this in such a roundabout way? Why not just... kill everyone? Or target 90% of the population but leave remote tribal peoples alone if they want to preserve "some" human life?
I'm pretty sure the theme currently is they didn't do that because they are "benevolent". Maniacally benevolent. I don't know why I'm missing so much stuff while watching this show, I blame it on high stress caused by my job but yea the religious themes are becoming more prevalent.
Carol and the 12 apostles, benevolent, psychopathic, manipulative leaders. It's an allegory about religion. Probably.
This is the part where it is necessary to differentiate the alien from the hivemind itself. I kinda explained this a bit before but what the hive wants/what rules it follows it was specifically designed/programmed to do, and it is wholly separate from what the alien intelligence that designed it wants.
As a weapon it was clearly designed to infect everyone while also acting in a way that assures the destruction/extinction/complete subjection of the infected population. It doesn't know what the aliens who designed it knows or wants, it isn't connected to them at all. It has a series of biological imperatives that it instinctually follows, the end result of which is, unknown to the hivemind, the extinction of the target species. The most novel thing here is that instead of being some plague or killer zombie virus infection it is this super nice hivemind infection. But it still has this instinctual need to infect everyone.
If it was designed solely as a killer virus that just killed the infected then you run the possibility of immunes surviving, survivors killing off all the zombies, whatever, and rebuilding society, so this virus was engineered specifically to rectify that to prevent any survivors via niceness.
That, and the fact that the signal was sent via radio waves which took 600 years to arrive, indicate that the aliens aren't some super galaxy spanning advanced species with FTL travel or wormholes or teleporters or whatever. They discovered us, they designed and directed the blueprint for a virus that would pacify us, to ensure that we were either completely dead or, at a minimum, the handful of survivors were completely subjugated and at their mercy when they do finally arrive to our planet, thousands of years from now.
If the virus was designed in a more traditional way as a plague or zombie outbreak or whatever it never would of made it out of containment.