>The loophole is to classify them as “light” commercial vehicles.
Not a loophole. There are (broadly) eight different FMCSA classifications; and a CDL is usually required only when the GVWR is at or over ...26,000lbs. Everything below that is medium or light duty. Heavy-duty is the upper end of class 6 (think school busses), class 7 ( garbage trucks & cement mixers ) and class 8 (18-wheel semis).