Harassers can set up another account, but they generally don't. And not seeing the harasser's messages is not the only goal - when you force the harasser to unf

Harassers can set up another account, but they generally don't. And not seeing the harasser's messages is not the only goal - when you force the harasser to unfollow, they don't see and harass your retweets either. The goal isn't not to be seen - people already know about protected accounts. The goal is not to be harassed.