The Wikipedia article says that sorghum is used to produce alcohol. So, lets see, what would they have chosen for dinner? Grain-based food such as bread, or steak and a beer? :-)

If other food was plentiful, why would they work at processing sorghum? Alcohol could be the answer. Perhaps a more detailed look at the artifacts would give us a better answer.

Just throwing in another thought. The fact is, there is much we don't know about the sorghum on the implements found.

- Wayne