The number of flags required to statically compile stuff when using cgo is indeed a bit complex (if you're not using cgo it will always statically compile), partly because interfacing with C is a bit complex.
There is an issue to make it easier[1], and doesn't seem too hard to find more information about it[2].
More general: I think I've seen every language described as "badly documented" at this point. Someone new comes to the language, knows what they want to do, gets stuck/frustrated because it's a little bit outside the "mainstream path", and calls it "badly documented".
[1]: https://github.com/golang/go/issues/26492
[2]: https://duckduckgo.com/?q=go+compile+static