From the fine article, emphasis mine:

> He says seven deputy US Marshals showed up at his home with guns and took him to federal court where he had to sign a payment plan for the 29-year-old school loan.

He was not taken to prison, he was arrested. These are wildly different actions. Nowhere in the article do the strings "prison", "jail", "gaol", "cell", "penitentiary" or any other synonym for prison appear.

There is plenty of discussion elsewhere in the HN comments on what may have led to this arrest.