My grandson is a water hound, and that fact plus his third birthday put us last weekend at one of those modern waterparks owned by a conglomerate on the New York Stock Exchange that features hair-raising water slides, wave pools, massive downpouring fountains and godawful unhealthy food at exorbitant prices. It’s a decidedly middle America, working class, family entertainment vibe, which today means plentiful diversity not only of ethnic groups but also body types and aesthetic sensibilities. Suffice to say no one would mistake it for the starting line at the Ironman Triathlon. Why is it, then, that the more…