Now Casey is going to take the PGA to court. Doubtless he will argue that the PGA rule impedes his ability to make a living. Perhaps he will claim that the rule discriminates against him. He is a university graduate and a plenitude of job opportunities are available to him. As for the disadvantage he suffers from his physical condition, it is not all that unusual.
Most athletes are at a disadvantage against the greats.
A range of aids might make us more competitive, from drugs to equipment changes to illegal golf carts. Steroids would make a weaker athlete stronger. Special poles might allow a pole vaulter with a bad back get over the bar. There are great amateur swimmers who have been held back by allergies and asthma. Were they allowed access to medication that is banned for its side effects they might be world record beaters.