User blog comment:IamJakuhoRaikoben/Jak's Back! And Condensed Chapter Reviews./@comment-120.28.78.135-20130403040127/@comment-7418318-20130403072138

Maybe he was overlooked because he's constantly gone one some long term quests.

Or maybe the title is about more than just raw power. His tendency to destroy things by mistake surely won't help much in getting on the good side of the council (or whoever gives out the title), even if they weren't prejudiced against Fairy Tail in the first place.