An individual fact isn't copyrightable, a collection of facts can be. Details vary by jurisdiction, but in an international project like OSM you have to comply with the strictest jurisdiction
The address alone is a single fact, but its context on a map that allows it to be found is a collection of facts
As an OSM contributor in the UK myself and my peers only use clean-room data ( firsthand visit ) or data from public sources ( planning applications etc )