The best revision as a rebuttal to the counterclaim is:
Golfing is an excellent form of exercise, with the average golfer burning over 700 calories by playing a nine-hole round of golf, and requires strength and flexibility.
This response directly addresses the counterclaim regarding the physical exertion of golf by highlighting the physical benefits and challenges involved in playing the sport, effectively supporting the claim that golf should be regarded as a sport and that golfers are athletes.