Googlers: Ensure you're using out of band communications for all organizing efforts. I've heard good things about Signal and Matrix.
Horrible clickbait article. This is about internal discussion boards (Google Groups), not individual email accounts. And it's about community moderation, not union busting.
No one is forcing the talented engineers working at Google to work there. Especially when a do-not-evil-motto company is monitoring (AKA reading) their emails.