OpenStreetMap in general seems to have way more contributors from Europe: https://www.osmstats.neis-one.org/ https://www.osmstats.neis-one.org/ But in this cas

OpenStreetMap in general seems to have way more contributors from Europe: https://www.osmstats.neis-one.org/ https://www.osmstats.neis-one.org/ But in this case perhaps much of that data came from a data import that didn't have compatibly-licensed data for the US.