Good post. I would imagine that most here have no experience with walking 18. Riding 18 = Not bad doesn't seem like a real sport.
Go out on a Saturday afternoon when it's 90 degrees and high humidity and walk 18 holes. See how you shoot and how you feel.
Last year during a heat wave in Los Angeles I walked 18 holes in 117 degree heat. I know - I'm an idiot. I still shot in the 80s but was struggling on the back nine to make it. Thankfully it was a flat course and easy to walk (under normal conditions).
By the way GOLF IS DEFINITELY A SPORT.