though it seems genuine asthmatics or others with so much as a slight wheeze are looked at in distaste by too many people.
There is no distaste - any prejudice is being held in your head. You asked a very direct and specific question relating to a very demanding job and got a direct answer - any perceived risk, no matter how slight, is worth eliminating, so that is what the Med Board does. Are the OASC pers really saying that because of that you're a second class citizen? No.
You analogy that follows the quoted passage is poor, I think you'd find blind people applying to be Pilots in the RAF would be given equally short shrift by the recruitors.