As an educator, you are responsible for the language or content that you post on social media. It is your responsibility to research how to properly set-up your privacy settings. You are also responsible to conduct yourself in a professional manner in public. Anyone can snap a picture of you now a days. I tell my students if you don't want on social media, then don't do it. I also tell students to treat other as they want to be treated. Cyberbullying is not ok. Someone needs to develop an app to ask a persons permission before being able to post comments or pictures about that person.
I agree that it is important to think about and analyze anything posted on social media or websites before posting it to ensure the privacy of students. Teachers and various people have done experiments and posted something to see how many likes they can get or how far it will go, and they have been surprised at how far it has gone, even to many, many foreign countries. It is a good and interesting message to send to students, that if they don't want it posted on social media, not to do it. It's good to encourage conducting themselves well always, and to model that as educators and parents.