Comment by seba_dos1

There's no such message there, it was a description of a situation written by me and it doesn't even actually match the git's lingo. Should have made it clearer I guess.

It is surprising. You wanted to edit the value of `main` ref, yet suddenly you now edited `HEAD` too without meaning it. Bailing out and letting you actually decide whether you want to do it or not is the correct thing to do for a high-level command like `git branch` (alternatively it could ask you what to do interactively). If you don't want such safeguards and you know what you're doing, use `git update-ref` which will happily let you break whatever you want.