Rules around preventing a hostile work environment don’t place an obligation on anyone to prevent it at all costs. It means that if an employee or - more relevantly here - a customer - is being hostile, then the workplace needs to make sure the employee or customer stops. But if you work in a call centre cold calling people, your company isn’t going to get fined if you get an earful of abuse. (They might get fined for cold-calling depending on specifics :P) Same here.