Upstream's irrelevant to a maintainer. Downstream? Maintainers typically know best, that's why the user chose that distro. I bailed on Debian when they decided to go systemd. That's Democracy.
Actually that's not even fair to Go. I'm as annoyed as anyone about the many suboptimal technical choices of the Go team, but I would say that Theo saying "I have altered the ABI. Pray I do not alter it further" is quite accurate.
Go in this case made a choice based on one "promise", and OpenBSD changed the deal.
Even Hyrum's law is more about "as implemented". Go actually went with "as designed, in the last, what, four decades?". Syscalls actually did use to be the API, and statically linked libc really did use to be "ok".
OpenBSD let security be done though the heavens fall, and that's fine. But it's MUCH easier than the alternative. So obviously much easier to make progress on.