User blog comment:ZorroOfTheBronx/Boomerang Channel to Broadcast YJ Reruns November 3rd/@comment-5553705-20121101012447/@comment-4928331-20121104090816

The most likely explanation is they want to preserve momentum. If they ran Season 2 now, they'll be out of episodes by Decemer. But if they start running on January 2013, they'll be out by the end on March, which is also when Teen Titans and Beware the Batman will take the places of GL:TAS and YJ.