I think it takes a lot of guts to put your relationship status on facebook, because the humiliation/shame of having to change your status that you are "single" again creates the stigma that you're on and off relationships and can't find anyone steady.
However in one case, I know this chick who was in a relationship in college up until senior year, and never indicated that she was in a relationship. Now we both graduated, and she works in an industry that requires one to be very social. She removed that hidden status (I was never friends with her on FB) but now it shows that she's "In a Relationship" with someone.
I believe this is to prevent coworkers and other acquaintances from hitting on her and making advances. Anyone with a facebook account can stalk her public profile and it'll show that she's in a relationship.
This prevents further creeping/stalking and I agree with that.
It doesn't matter if a guy is Single/In a Relationship. It's only for chicks. That's what I believe. I'm tipsy and sleepy, and I won't elaborate more on that.