Better explenation would be that the existence of the concept of lies and deceit would inevitably lead to disharmony due to a deterioration of trust within the hive mind and result in a fracturing of the civilization. Complete trust in mutual benevolence is a foundation for a hive mind to function. It may be interesting to speculate what would happen when suddenly the ego focused world view of a human gets introduced to the Thargoids when Seo enters full rapport with the hive mind. Would she end like a drop of fresh water hitting the ocean or more like a steel point penetrating safety glass?
The idea that a hivemind cannot have individual thoughts inside it relies strongly on the idea/definition that individual thoughts/minds do not exist inside it. Which I think is either outdated or doesn’t apply to the Thargoids.
Queens are very clearly sentient, however, or at least said to be. The average Thargoid drone is not, instead guided by the queens, and possesses less advanced intelligence. Each one of those will have their own thoughts.
So my idea here is that Thargoid hive minds are not “traditional” hive minds - they are still connected to each other, yes, but it exists more to allow faster transfer of information and/or communication between each member of the network, rather than it being a Borg-esque army of mindless husks where free will and individuality doesn’t exist.
The different reactions of Thargoids in the leadup to the war would indicate so. The Coalsack Thargoids apparently never took aggressive actions against humanity in there, but only huddled up around barnacle sites.
And let me just remind everyone how the Alliance has a barnacle neatly wrapped up inside a research station in the California nebula, but our flowery space neighbors are totally fine with it*. (Galnet also sorta lied about the supposed aggressions of them leading up to the war… unless that was a Frontier moment and never showed up in-game.)
If they were all the same raging, mindless beasts where everyone shared the same views, why do we have such situations existing? It’s almost as if Thargoid hives are made up of many individuals sharing their thoughts with each other, without all thinking the same thing all the time. A fitting line from a data pad in Subnautica…
“We would do well, as scientists, to remember that our goal is not to paint the world as we see it, but to see it as it truly is.”
*I’m not counting Delaine’s idiocy in claiming imminent Thargoid attacks when he prompted them to defend their stuff in the first place, by pillaging barnacles to depletion the moment he took over. The goids there seemed to be fine with the Alliance for years until he showed up under false pretenses.