I don't have a Facebook account, but I sometimes just browse some publicly available fanpages on Facebook. It was always possible without having to login. However, since maybe two days, when I try to access them, Facebook asks me to login.
Tried clearing cookies, turning off uBlock, accessing Facebook from a different browser (even newly installed one) - still no change. Were there recently any changes on Facebook (that you are aware of) that require everybody to login, even only to just browse a public fanpage?
Or does it happen just for me, but in that case why, and how do they recognize my computer? Did they "restrict" my IP address?