Exceptions to hair length rules: Nazirite vows, philosophers, and the principle behind exceptions

Nazirite vows (Numbers 6, Samson) involved not cutting hair, but the purpose was separateness from normal behavior, not looking feminine. Samson would have had a long beard too. Philosophers had long hair as a sign of simple, extra-societal lifestyle. Epictetus acknowledged: if someone is naturally hairless, that's nature and not shameful; but deliberately making yourself look like the opposite sex is wrong. Craig Keener notes Paul would have been aware of exceptions, suggesting this is a general rule, not absolute.