There is even a small amount of hierarchy at our 15 person Thanksgiving family dinner.
Also hierarchy doesn't mean that there is a single individual that's at the top. There could be a series of caste hierarchies, where groups of people were considered "better" than others.
We don't know if everyone from the tribe was in the common grave or a select group of people.
You're building a narrative based on your knowledge of other civilizations histories and understanding of modern day social structures, and assuming those traits must apply to this civilization. The truth is, we don't, and likely won't ever, know how their social hierarchy was built. Anything said is speculation. This isn't the case where you can be 80% confident something is true, more like 2% confident based on the discovered evidence.
If that's an accepted idea in the field, hopefully it comes with a lot more evidence than bones being mixed, as future archaeologists might find in many of our cemeteries of today.
The above comment also illustrates their biases. They map their knowledge to history that came much later to the Tepe sites. Stating that it was "was likely only the craftsmen or shamans" is a prime example of that.
To know that, we'd have to identify the bones of an important leader in a mass burial site.
We don't know that.
