Slack now has the outage listed:
https://status.slack.com/calendar
The online cynicism is something I've never understood. It assumes the world is filled first first-order simpletons & somehow only the poster rises above it.
People aren't dumb & companies aren't dumb. People will notice a status tracker isn't accurate. They will have reduced confidence in the company. Companies know people will notice & think this way, so they generally don't engage in this type of deception. I'm sure there are exceptions, but in general, status pages have tended to be accurate in my experience.