Flustered? LOL, I do not think that word means what you think it means. . .
Understanding that people can be attached, both literally and emotionally, to their hair, is fairly logical. Given that it's very commonplace. That is why it is understandable that people who suffer alopaecia (sp), lose their hair as a result of male pattern baldness, or as a result of chemo, are distressed. It's not 'just hair' to them. It's part of them, part of their identity. Obviously this is something you do not identify with, and that's okay, but I'm sure there are aspects to you that make up you, that mean a lot to you, but another person might think - can't think why you care that much. That doesn't mean that you shouldn't. Just that you have different values and priorities.
And whether you care or not, nobody has the right to vandalise your person, which is what this young man did to this young woman when he hacked at her hair without her consent.
He is the one that needs to learn to keep his nasty little mitts to himself, not her, needing to learn not to care about her hair.