WHat reason does ishmael postulate as the basis for radneys pettiness

Radney's major beef is with a guy named Steelkilt. Radney is a Nantucketer and Steelkilt is a Lakeman (from the shores of Lake Erie). We have a whole home turf conflict going on. Apparently Radney hates "backwoods seamen" which is the basis for his problems with Steelkilt.