Why won't my girlfriend update her relationship status on Facebook?

My girlfriend of one year has recently updated her Facebook job status since starting a new job. Her relationship status stays the same- "married to her friend" (she's female).

I've asked her this before and she's just told me that "Facebook isn't important, nor should it make any difference in the relationship."

Everyone knows we are together since our profile pics are of each other, she's put photos up and posts about us, etc. Should I say anything else? My parents have advised me "it's only Facebook, doesn't matter, and everyone knows you're together anyhow.