How 'Fearenside' became a decent character?

Fearenside is a man who hauls luggage that belongs to the stranger.  His dog gets upset at the stranger and attacks him, ripping his pants, exposing his dark leg.  Later when Fearenside discusses this happening with Henfrey, he just assumes that the stranger, who has a pink nose and black legs must just be multi-colored like a "piebald horse."  This is a relatively charitable statement, assuming that which is more positive than negative.