Unfortunately yes they are. Your lucky thats all they did. Ive heard where people post mean status updates friend:unfriend people, poke, you get the idea. It's an invasion of privacy but that's why fb is password protected.
Are we talking about parents? They have a right if suspect something going on. Same time people are curious and you leave something open people are going to look. Hard lesson for you. By the way. Don't post anything on Facebook you don't want people to read.