But honestly, even if it's proprietary, OpenStreetMappers don't mind. We're happy that someone is using our data, that's what we are there for.
Now, what you are looking for is probably something along the lines of uMap http://wiki.openstreetmap.org/wiki/UMap which has something like a WTFPL license https://github.com/umap-project/umap/ and which is something I point people to. It's lacking the design flair of this product but it's probably a bit more feature rich.
Particularly since the author does not appear to be meeting their burden under the OpenStreetMap license.
"You are free to copy, distribute, transmit and adapt our data, as long as you credit OpenStreetMap and its contributors."[0]
"We require that you use the credit “© OpenStreetMap contributors”."
"For a browsable electronic map, the credit should appear in the corner of the map. For example:"
There might be a bug or two to work out, but they clearly aren't ignoring attribution.
I'm still looking for a FaiF version of something like this - does anybody know of one? Seems like a slap in the face to all of the OSM developers to use an entirely Free stack with a proprietary veneer on it.