More straw and/or false equivalency
Not locking doors is the equivalent to not having a police force rather than having checks at internal boundaries. I guess the closest analogy involving locked doors would be something like, "do you lock all the internal doors in your house at night ?".
Friends who were burgled a few years ago and are (IMO over) cautious do, but no-one else I know does. Even they don't lock the toilet doors from the outside.
To instate (or re-instate) border checks, first I think you need to demonstrate that they'd be effective. In the case of borders in Benelux or between France and Benelux, France and Germany and so on there are so many crossings that, unless you build a wall all the way along the border, the "bad guys" will still slip through whilst law abiding travelers will be inconvenienced. even with a wall there's no guarantee of effectiveness.