The article fails to address the central question over why the legend of St George has provided a source of inspiration for English people over the centuries. The reason is because of what the legend represents - the triumph of good over evil. The origin and nature of the man himself is of little significance.
While it may be true that the majority of English people do not overtly mark the day, I believe that this is indicative less of a lack of desire to rejoice in our achievements as a nation but more to do with feeling uncomfortable with the concept of celebrating an English national day.
This is engendered in no small part by a government that cares little for England as an entity, television controllers that devote no air time whatsoever to signifying St George's Day and journalists who seek to dampen down any enthusiasm that may spontaneously erupt.