Which it can't do because, as mentioned, Go randomly iterates over maps. That's the data structure that most would use to load arbitrary input files into the program.
If you have a hammer in your toolbox, it doesn’t mean you have to use it in every job. It golangs maps don’t do what you want, pick a different data structure.
This is like claiming that, because updating native integers isn’t guaranteed to be atomic in a language, you can’t do multi-threaded programming.
This is like claiming that, because updating native integers isn’t guaranteed to be atomic in a language, you can’t do multi-threaded programming.