This is similar to other reported actions that impose barriers on employee communication like limiting the number of employees that can be on an unmoderated email list in the wake of the firing Emily Cunningham and Maren Costa, and moving mailing lists to slack. The timing of these actions seems to always coincide with an internal tool being used to organize groups of employees around issues where Amazon seeks total control. Amazon used to encourage tech employees to visit FC's to understand how they operate. I've heard they've stopped that too.
https://www.theguardian.com/technology/2020/apr/14/amazon-wo...