Its difficult to analyze that statement without knowing how much they they were carrying. Was in a baggy or a pickup full.
Very few are prosecuted for small amounts (should be zero) most all are trafficker's, distributors, transporters and dealers.
Those are recorded separately from possession: https://ucr.fbi.gov/crime-in-the-u.s/2019/crime-in-the-u.s.-2019/tables/arrest-table
The records are misleading because most first time or small time time offenders are given the option of pleading down to simple possession. They were arrested on higher charges. That's the way the system works.