I'm sure it's for the same reason I won't check it at work.....
While I love bewbs and butts plorsted here to admire at home while I read through......it's a little difficult to convince your boss if he happens by while you're scrolling through the SportsHoopla that you're only trying to read the plorsts.....lol
....edit, and right now I happen to have a female boss to boot.....