Having no friends usually is associated with sadness but some people actually associate it with determination and ambition as “friends” are distractions. If you only have acquaintances, an alternative grouping might provide a better framework to explain and reason about it.
The overall model provided is a good starting point but seems to assume some general human kindness that might be far from real. Interactions might be faked on one or both sides, relationships usually are not symmetric, people have a difficult time adjusting their interpretation of the real world accordingly to the inputs they receive, and so on.
I usually do not use the word friend for people that I mostly interact because of a shared hobby nor for social acquaintances, but I understand that they fit the authors definition.
In practice the text has more value if you replace “friends” with “people you interact with” and if you add a “none of the above” category. Which does not diminish the value of the article in any way.