Well it can be pretty personal. Plus they changed his profile picture to something intentionally damaging. If you log in as someone else, you get access to their private messages. You can send messages or make posts as them or delete old ones. You can see a history of where and when they logged in. You get access to photos and posts they haven't made completely public.

Anyway if you're not lucky enough to have friends and customers physically nearby, social media could be your only connection to close friends or critical business contacts. Messing with that could really make someone's life difficult.