Yes certainly. Were Justice Camp to repeat his error, then lack of competence would have to be considered. 

But that hasn't happened. Quite the contrary. Justice Camp, on his own accord, took remedial steps to correct the deficiency in his legal understanding. That, his sincerity, and the notoriety of the case should be enough to ensure that he doesn't make a similar mistake in future.

According to the feminist law professor who interviewed and instructed Justice Camp, his mindset was not "unbelievably unsuitable." While calling some of his comments wrong, she noted that his mindset was not that of a misogynist. She even testified on his behalf before the Judicial Council. I believe that she's a better judge of the matter than you or I.

Competence in any complex task is not determined by a single failure.