You assume Facebook - or indeed the whole tech industry - makes products designed to fulfill a buyer's need.

They don't: they make surveillance products that also happen to have a function that you want enough to buy their surveillance devices.

GM sells surveillance vehicles because people need to go places.
Google makes surveillance software because people need a cellphone and a search engine.
Facebook makes surveillance glasses for perverts who need to record people covertly.

They all have a target market to sell surveillance shit. Facebook's happen to be consistently the creepiest.