The passage reflects the regulation of the clerical hairstyle from the 6th, not the 2nd century. The exact sense of 'comam nutrire' is debatable.
The remark may have some anti-barbarian sense. By 416 a law was issued prohibiting wearing long hair and garments made of animal skins in Rome (Codex Theodosianus, XIV, 10, 4).
It may be also aimed at some radical ascetic currents.