I agree we should preach mission, mission, mission to our young men. That being said the Lord has said Thou Shalt not Kill. Yet he commanded Nephi to kill Laban. A general authority told Dale Murphy not to go on a mission. Jimmer's mission of representing the Church has been an incredible one.
For the man that Jimmer Fredette is, perhaps he did not need that training that we did. The Lord has a plan for us all and even though on the surface that plan may look one way it isn't always the case.