From the engineer's medium post:
> For example, someone changed the default desktop wallpaper during the walkout last year so that the Linux penguin was holding a protest sign. The company has never reacted aggressively in response to a notification such as this in the past. It’s always been a celebrated part of the culture.
I suppose this was her mistake: ""It's always been a celebrated part of the culture"
Google clearly does not always operate in good faith with it's employees on labor relations issues. The correct approach for her to take would be to get written approval from her manager on the popup
Her job was supposedly to "write browser notifications so that my coworkers can be automatically notified of employee guidelines and company policies while they surf the web", and this was supposedly a notification of one such company policy, but it was naive to think she could just approach her job in good faith and be treated in good faith. BigCorp follows the law of the jungle, and workers are not unionized at google so every engineer has to cover his or her ass before treading into contentious waters.
For what it's worth, after reading both points of views I think her actions were highly reasonable. But I would never implement that kind of notification like she had done, not without written approval from my boss and maybe my bosses' boss to cover my ass.