Today facebook has demanded that I upload a photo ID from a state-issued driver's license, passport, military ID card, etc. before I can log in again.
Facebook wants/demands that users use their real names. This is not new, but FB has been enforcing it much more over the past year or so.
The reason is simple, even if FB won't admit it -- they want to match a name with your FB posts, likes, interests, etc so they can more effectively sell that info to advertisers and marketers.
Collection and sale of that data is the only reason Facebook exists.
Facebook likely exists to find peeps to put on the no fly, no buy lists.