Maybe club soccer is more about the name on the back of the shirt, and high school soccer is more about the name on the front of the shirt. Not too many folks get "warm & fuzzy" about club soccer. Probably because many of the parents have become rather tired and jaded over the years.
I was at the Discoveries tournament at Manchester Meadows in Rock Hill this past weekend. It was a classic-level tournament. The most spectator passion exhibited was by the parents of Strikers of Gaston County Soccer Association (SGCSA). Teams from this little club won the U-16 Girls and U-13 Boys bracket championships. The parents were going nuts! Honking air horns, ringing cow bells, chanting the team name!
When was the last time you saw something like this at a R3PL or Academy match? It would probably be considered "immature behavior".
Point being, IMO, passion for club exists at the younger and lower levels. Passion for high school seems to exist all the way up the line.