> internal security mechanism

Correction: an internal message display tool.

> for your own pet activism

> push your slogans

Correction: a warning not to break federal labor law, which Google is actually required to provide.

https://miro.medium.com/max/2000/0*1BTVYLTvuHiJVvp_.jpg

> Do you activism in your personal time.

This is about Google. Apparently their company culture has been the opposite, and they have commonly had lots of political discussions on company time using company resources.