That sounds like it's actually very difficult to support multiple operating systems. As a developer I never, ever want to write any OS-specific code. Sure, that's sometimes required, but saying that the solution is to have multiple files, each for a single OS, doesn't sound good. It's a lot better to abstract the OS away. Node.js does this quite well. Seemingly a lot better than Go.
Besides, Node.js doesn't need to be compiled for each system. This alone makes Node.js better for writing code for multiple operating systems.
>Go is a compiled language so distributing applications for use on multiple platforms is just easier.
I disagree. You need to compile to code for every single platform, making code distribution costly. With Node.js you can simply distribute the code as it is and it probably works in any platform. (The probability is as high as it is for Go assuming no extra work for a new platform). Sure, each platform needs to have Node.js, but Node.js is supported in most platforms.