But then security authentication is one of those functions whose philosophical concept is hampered by self-contradictory details of its own design. To pick a topical example, it is the right of European Union citizens to enjoy free movement between EU countries without being stopped by border controls. However, how can the border controls know whether you are an EU citizen or not unless they stop you to ask for your EU identification? So it's only by presenting your passport or ID card that you can exercise your right not to have to present your passport or ID card.
FoM is more about having the right to live and work on equal terms in other EU countries.
Schengen is the right to not be stopped by border controls. If you fly from a Schengen country to a Schengen country, you won't have to present your passport/ID card in the destination country. If you go by car, you won't get stopped at the border, you just pass the country's roadsign (if there is any) and be happy you've taken back control.
The counterpoint to FoM and Schengen is having to register your residency and having to possibly put up with more stop and search.
Silly rEU countries, if they didn't have FoM (the UK is about to get rid of it) and didn't have Schengen they could have intra-EU border controls and stop and search just like the UK... all the responsibilities, none of the rights. Who'd vote for that? Oh.