Board Thread:Episode Discussions/@comment-1181222-20170906103845/@comment-5085906-20170907162524

Another possible explanation for that is that they haven't learned proper social etiquette and are dangerous to let roam around other kids. At least Sumire hung out with other kids - these guys were in a cave with a mad scientist who raved on about evolution and was quick to put them in line with his own visual prowess. Letting any of these participate in the Chunin Exams or enroll into the Academy would probably make for a repeat of the Zabuza incident.