The point is that since there's ~nobody with his first/last name combo people will assume it was him. Whereas if there were many people with his first/last name combo he'd have a default defense (it wasn't me). In fact he wouldn't have to defend at all since whoever does a background check would immediately see that there are multiple people by that name.
Sure, but that's just a simple case of mistaken identity. Impersonation is deliberately pretending to be someone. The uniqueness of your name doesn't help at all then.
