most if not all people who work like to keep their job and home and leisure activities separated. some work laces, agencies, groups, have rules that dictate whether the employees or participants can "friend" each other outside of the job or group....

think of it like here... would you like one of your outside of psych central friends and family to suddenly show up here on psych central and send you a friend request...

my job has rules about things like blogs and internet social networking places like facebook. my work has a facebook account for employees for work related issues. I have a separate facebook account for my friends and family, and another one for gaming due to the games you need to sometimes add people that you dont know to the games as "neighbors" in order to accomplish the gaming tasks/goals/....I dont want to have just any jane and john doe on my regular friends and family, post my daily life kind of facebook account, thats just inviting trouble to mix strangers/ possible stalkers or other disreputable folks into knowing my daily routines and daily life... I also have a work related facebook account that is protected (closed group style) account. this way there is no conflict of interest, confidentiality issues,

my point is your co workers may be blocking you because they want to keep work and home life separate. they dont want their co workers to be in their personal life, knowing every little thing about them.. just like you would not most likely like all your co workers to come read your posts here on psych central .... huge conflict of interest and breach of your rights to be here with out your co workers finding you and friending you here.