The subtext seems to be a hostility towards people making money from what you've shared.. which I find sort of baffling - but is very on-brand for the general anti-capitalist sentiments in the memesphere. People building on your work feels like something to be celebrated, but I guess it's a difference of opinion. I'm just generally skeptical that this would be "killing the project" at all.. it feels like it'd be the other way around? If OSM data were for instance used by Google and Apple Maps.. it feels like it'd just have made it more foundational and would get people even more excited to contribute. It'd be the world's central repository of map data everyone builds off of.. like the Debian of maps. Instead it's a parochial project for map nerds.
Can you imagine if GIMP has a similar policy to watermark all it's output with a "Made my GIMP!" in an effort to "attracts the flow of new contributors" and to make it hard for people to build a product with it?