@NewtonMark

There is a part in there which is demonstrably bullshit:

Slack can’t access the underlying content. We have various technical measures preventing this from occurring. Please read our security white paper for more info on these controls that protect the confidentiality and security of Customer Data.

Nothing in the linked security white paper states how “Slack can’t access the underlying content”. Besides, there is no underlying content to “Customer Data (e.g. messages, content and files) submitted to Slack as well as Other Information (including usage information)”. That’s all your (as a customer) data right there.

Get out while you can!