What you are saying is you want to make the NFL practice illegal. Fine. But that's not the same thing as the rule being illegal today. It's not.
That's just crazy talk, you don't get to choose based on orgin of birth, religion, age, skin color, so don't say they get to choose based on whatever an employer wants.
Secondly businesses are required to accept applicaton from all quailfied applicants.
Has the rule ever really been challenged? Since court cases tend to take years, has any player ever bothered to make the challenge and take it all the way to court? Why make a challenge that would probably last longer than most pro careers. But if no one has ever challenged the rule, then how can we say that it is definitively legal?
On a separate unrelated note, would the CFL even be relevant to the court fight? I'm not sure that the argument that one could leave the country to work would matter to a court deciding matters within the US (I'm assuming Arlen Spectre isn't involved *g*). In terms of a US case, the relevant alternatives to the NFL would be some of the semi-pro leagues and the Arena league. Though, I can only recall Eric Swann being the example of a semi-pro player who was drafted so that might not be a good example.