If the argument being made is ".NET isn't a language", and the response is "okay, then how do I install C#?" Linking the dotnet website probably doesn't advance the idea that C# and .NET aren't tied together.
How do you install Java? First thing you'd do is download the JDK. Is the JDK a language? No, it's not.
That's a fact, not an argument. And who said that C# and .NET aren't tied together? You install the runtime/SDK to get started with the overall environment, similar to many other programming stacks.