The gist of it is that an intransigent minority can often dictate the choices of a flexible majority. It is unwise to make decisions based solely on majority rule, as stubborn minorities can affect complex systems in ways that you do not expect. The phenomenon can be verified in a variety of situations across history.
To put this into context for Slack, I believe technical users have been particularly important for the app. Tech users were early adopters for Slack - I'm sure a lot of corporate accounts started out with engineering teams. Tech users wrote the chat bots and integrations that Slack is known for. They got people to use Slack, and they can get people to stop using it.
Let's say you're changing the way a certain feature in your application works. The majority of users are happy or indifferent about the change (but weren't particularly bothered by the old behaviour). A minority of users not only reject the change, but are vocal in how much they hate it. They will not tolerate the new behaviour, and will try to get other users to abandon your product unless you resolve the situation. What do you do? You can ignore them for now, but can you predict the long term effects of turning your back to the intransigent minority?
1. https://medium.com/incerto/the-most-intolerant-wins-the-dict...