[SamWhited]

Organic Maps is a way to distribute OSM data, but it also has a lot more than just the OSM maps it uses (code to curate and collect those maps into downloadable packs, code to display them, code to do routing, design assets and resources for the app, documentation, etc.)

You're correct that the maps are OSM though, you can always contribute to OSM and that will also help Organic Maps (or whatever new community based map project comes out!)