Earlier quoted context omitted.
I don't think it's so black and white: the "security tool" is a chrome extension for sending notices to employees about the site they are visiting. An analogous situation seems like if the company had a big cork board for safety/security messages and someone posted a paper with that sentence on it next to something the company posted that was perceived as anti-union. It's unclear to me if that other scenario is prote…
"...presumably you couldn't stick such notices just anywhere." Nor use company resources/infrastructure to distribute it.
https://www.post-gazette.com/business/career-workplace/2019/...