I agree with @dev360. I think it has to do with RavenDB being more common with .NET developers (at least from my experience).
Hm, isn't RavenDB a .NET solution? As such how could it not be "more common with .NET developers"?
The original client was written in C# but I believe there is Java and JavaScript clients now. Also can be queried via http requests.
RavenDB is just a server application. There's nothing stopping you from connecting to it via, say, Python.
It's just much more commonly used in .NET apps.
Then count me in the category that requires you to use the qualifier "almost". I've been working in .NET since it was invented and I've never heard of him.