You are using 'map' to mean 'a rendered image of some raw data'. Then while the rendered map (on paper or whatever) is clearly copyrightable, you believe that the underlying cartographic data is not.
On the other hand, I believe that the data is the map; it is in computer-readable form (as well as being human-readable and human-editable, as OSM shows) but it remains a map. Similarly, a musical score kept in computer-readable form in a music editor program remains music, and is copyrightable in just the same way as a printed music sheet or a sound recording.
In general, copyright status does not change when putting something into a computer or taking it out. Nor just because you express it in a novel form which can be manipulated by computer. That is why electronic books are copyrightable the same as paper books, MP3 files the same as vinyl records, a computer dictionary system the same as a paper dictionary - and, I suggest, a computer-readable map just as much as any other map. As others have pointed out, maps are specifically and explicitly *included* in copyright legislation.
Now perhaps some part of the OSM data set is outside the bounds of what has traditionally been considered a map, and so might be treated by the courts as more like a telephone directory (which is not copyrightable in some countries) rather than like a map (which clearly is). Another poster mentioned that turn restrictions on streets might be an example of this. But the truth is we don't know. I think it would be very unwise for anybody to start copying such information from OSM or from any other map (whether in computer-readable form or otherwise) and hope to rely on the 'just facts' defence in court.