The mountain most assuredly can play defense. It can seep water on the day you climb. Birds and small rodents can stroll out on your arm when you place a hand in a crevice. Or simply break off when you shift your weight. Is the decathlon an athletic endeavor or a sporting event? Is a marathon an athletic endeavor or sporting event? Are they really competing against another athlete or against the limits of their abilities and endurance? Where is the defense in the decathlon or marathon? Defense in the high jump? None? Are the Olympics not a sporting event filled with athletic feats? Are there no athletic feats within a sporting event? You are splitting hairs. Free soloing a sheer cliff for 4 hours is a real test of endurance, strength, flexibility, and serious mental toughness. The competition in mountain climbing is against other climbers. Can they climb what you just climbed? How fast can they climb it? Speed records are maintained. Was the easy or hard route taken? What equipment is used or not used? Defense does not make a sporting event or athletic feat.
Is it sporting event or athletic event? The same?