Facebook is like many other communities, only that it is a big one - and big organisations are hard to control.
Users become easily addicted, if they are not keeping their time spent "on-line" and the number of virtual friends under control. Also professionals should not spend too many hours on their daily computer work, which is, like many office and similar jobs, a sedentary activity, all the more, if their non-professional activities are also spent on-line. Facebook is like many other sites - useful, but it can become addicting and take all your professional and free time. Additionally, business, dating, politics, games, etc. involve certain risks.
Furthermore on-line communities, organisations, companies, websites and individual users are exposed to cybercrime attacks.
I don't think that deleting Facebook or some other popular community is a solution. It is more a question of dosing on-line work or fun, and of switching regularly to other, off-line activities.