This isn't about Slack, it isn't about US sanctions law. It is about any private entity creating closed sourced, remotely hosted software. Everyone knows that APIs can be pulled at any time (Twitter, Facebook, etc.) Spying can be mandated whether it is the US government, China, or anyone else.
As end users it is never clear what is going on behind the curtain. It is never certain the product will be here tomorrow - whatever the reason. No one would build a high rise where all of the elevators could suddenly vanish, yet we are increasingly putting the critical pieces of our businesses and our lives in the hands of entities that only need to flick a switch and everything instantly vanishes.
Governments of the Industrial World, you weary giants of flesh and steel, I come from Cyberspace, the new home of Mind. On behalf of the future, I ask you of the past to leave us alone. You are not welcome among us. You have no sovereignty where we gather.
We have no elected government, nor are we likely to have one, so I address you with no greater authority than that with which liberty itself always speaks. I declare the global social space we are building to be naturally independent of the tyrannies you seek to impose on us. You have no moral right to rule us nor do you possess any methods of enforcement we have true reason to fear.
You also wouldnt build a highrise where all elevators are built by a random Joe, who you arent even sure if thats his real name
But to clarify, they gave a service to people/teams who maybe they shouldn't have. Did the people signing up/using Slack know that? Maybe. Who's responsible to ensure it's enforced?
Slack.
When the law is as clearly wrong as this one is, it should be violated.
And something doesn't have to be morally good for stopping it to be morally bad. For example, playing chess is morally completely neutral, but it would be morally bad to attempt to ban chess.
Likewise, Iranians using slack isn't obviously morally good, it seems morally neutral, but enforcing a slack ban against Iranians is obviously morally bad.
What trade sanctions have been applied to Canada?
If Huawei didn't care about doing business with American companies or companies that adhere to American regulations, it wouldn't matter at all.
Actually, if you look at the image, Slack is beholden to US law, export regulations and economic sanctions - companies doing business with countries they shouldn't are in big trouble. See also: Huawei, who despite sanctions continued to do business with Iran, which caused the US to give them a huge fine. I don't know how that works given how Huawei is a Chinese company, but there you go.
To clarify: private companies are not and should not be above the law.