The Nazir's Mixed Messages

Is the nazir holy or a sinner? In Parshas Naso the Torah calls him holy, and a few pesukim later he must bring a chatas, and Rabbi Elazar HaKappar says the sin is that he denied himself wine. Yet the Ramban in Kedoshim praises the person who holds back from physical pleasure, with no mention of any sin. How can both be true? Rabbi Asaf Prisman finds a way through, and a young man comes back from a date to tell his Rabbi what impressed him most about her.