Anthropological: Benjamin is describing a social relationship between the king and the people. That Benjamin has been in the service of the people is expected. He is the king, it is his job to serve his people. However, it is also an expectation of many kings that they may enjoy their position based on the labor of their people. In this light, Benjamin clearly notes that he has not “sought gold nor silver nor any manner of riches of you.”
While we can take Benjamin at his word that he has not sought wealth at the expense of this people, and that he has not levied taxes (verse 14), it is also clear that he must have required something of the people. He cannot rule without some form of goods from the people to the central government. The most obvious case is the ceremonial architecture of the town. The people are met at a temple with walls. Neither the temple nor the walls were built exclusively by Benjamin – nor by any other single person. Such building projects require large amounts of labor which perforce removes people from other pursuits. It may well be that the majority of the building would have occurred in times of less intensive agricultural need (as is most logical as food takes precedence over building) but we should understand that while Benjamin did not enrich himself that does not mean that there were no communal requirements on the people. Benjamin’s point is not the absence of requirements, but that they have not been burdensome. In verse 14 Benjamin notes that it was his intent: and that there should nothing come upon you which was grievous to be borne."
The evidence of building alone underscores that there were some demands upon the people. Benjamin is not pretending that they have had no responsibilities to the king, but that those responsibilities have not been “grievous” nor for the intent of enriching the king.