Most likely your problem is with the Gerrit "Reviewers by Blame" plugin, which contextually uses the last editor of the code to determine who to ping to review the code. Makes total sense if the developers are still there, but that's obviously your problem - they're not there. https://gerrit.googlesource.com/plugins/reviewers-by-blame

The plugin also will determine if the user is "Active" - maybe what needs to happen is that the Go Devs need to make a sweep and mark everyone on their Gerrit who hasn't committed in say 6 months as not Active: https://gerrit.googlesource.com/plugins/reviewers-by-blame/+...

That said even after the cleanup of active users this is fundamentally a human problem with a part of the codebase that isn't being actively maintained.

As an aside - I really like Gerrit. It's leaps and bounds better than GitHub if your goal is putting code review front and center as the important task to accomplish, as opposed to search and making a fancy webpage. But YMMV.