Not sure if you didn't follow the link, or don't keep up with current affairs..
This has nothing to do with his decision regarding service in the armed forces. With the recommendations of senior military advisors, the Commander in Chief has determined that admitting transsexuals to the military is detrimental to combat effectiveness. This is not a military problem. This is a societal problem. Society is conflicted on this topic, and the military is a reflection of society as a whole. When we as a society have corrected the problem, the decision can be revisited.
If there was credible evidence that recruiting left handed Norwegians named Lars would serve to improve combat effectiveness, we should do a lot of that, too. In the meantime, anything that detracts from combat effectiveness has no place in the military.