It depends on what you mean by academically weak. As long as you define academic to be the ability of a pupil to pass an exam, then probably not. However, it empirically IS the case that people indoctrinated with creationism have trouble understanding many modern scientific theories & such people ARE academically weak in these areas.
Consider a situation where some idiot wanted to start teaching children that the moon was made of cheese. Would anyone find this less reprehensible just because such children could still pass exams & become good doctors, engineers, teachers etc? We do not accept such crazy logic normally, & we should not accept it as an excuse for teaching creationism.