They worked together but this was just a public discussion about a change to an open source projects' docs site. The response was private so he shared publicly because it's relevant info for the community. Everyone is screaming harassment, I don't see any evidence of that. Everyone's in the comments talking about professionalism, this isn't the time for professionalism. BLACK LIVES MATTER! Scream it from the rooftops…
Made me feel very positive to see this comment in the replies, thank you! It was very difficult to focus the discussion on Twitter to why the engineer would feel sharing publicly was necessary in the first place, despite potentially losing their job.