Oh gosh, the choice of language is such a context-specific design decision. The first versions of what became Docker were written in Python. The choice of Go was a mix of nerdy excitement ("it's like the best of Python and C!"), and adoption strategy: back then devops tools were segmented by language runtime: ruby, python or Java mostly. Shipping a compiled binary allowed us to be adopted by all tribes.
None of these things can be transposed today, so I guess I can't answer...
For what it's worth, my current project (dagger) is written in Go.
That's a good answer that effectively rebuts the article's claim that Go was a bad choice imo.
I interviewed Solomon about the Go history (plus some others) for this talk https://www.infoq.com/presentations/languages-cloud-native/
Actually there are some longer unedited versions I might release.