Faster. Higher. Stronger. Longer. 
Competition is part of our  DNA. To be human is to compete.
Since hominids first got up  their hind legs, millions of years ago, they have probably been trying to out-do each other in feats of strength.
As long as the athletes are strictly monitored medically, and the sport is policed and supervised, adults should be able to participate.
To not compete is to geld our species, or change us into something we are not.
And,
"Spectacle" itself  is surely amoral. It is what the participants bring to it.
 Jesus's "miracle of the five loaves and two fish", when he fed 5,000 people:  that would be good spectacle.
Trump speaking in Phoenix,  when he fed a small crowd a feast of vitriol and hate -- that would be bad spectacle.