That's nonsense. There are a lot of reasons that a first (or any) job isn't a fit, and a whole lot of them aren't caused by the employee's negative traits.

Just to name a few: the job description didn't match the actual job, overbearing managers, overbearing coworkers, uninteresting work, a better offer elsewhere, changing interests, or - just like OP - the employee feels like he would grow his talents better elsewhere. I have been in the same situation and employers have understood and respected my decision.