Yep, the world is full of A**holes. No changing that I guess. Of course, being an A**hole isn't illegal, yet. Blackbird.
No one is arguing that this is a good policy (as far as I have seen) on the part of the employer. It is a quetion of whether the owners of a company can decide who to hire and who not to hire. The reasons may be stupid, but oompanies make stupid decisions (and some go out of business because of it) all the time.
If the question were whether an employee should be allowed to quit a job for a stupid reason, such as because his boss smokes at home, almost no one would say that the employee should be forced to continue to work for that employer.
I will tell you this. If I owned a company, and I only wanted to hire people who could properly throw a frisbee, you can be sure I would do it.
The same people who say that bar owners should be allowed to control their property and allow smoking (which I agree with, despite being a non-smoker) take the opposite position when an employer doesn't support smokers. Pretty transparent.