Earlier quoted context omitted.
Slack has, publicly, a multi-member security team! That's entirely focused on the chat system that I don't have to put any of my teams time towards.
I'm curious... Which is more secure? A) Slack. B) Open source software on a LAN accessible only through physical entry, SSH, and/or a VPN.
I would say that Patchwork which runs on SSB protocol is more secure than Slack (if used on your LAN) and it's written in a freaking javascript.