Being a team player is measured by communicating and working together. It just so happens that in some organizations communicating and working together happens on Slack.

That was the point of my original comment: in one of these organizations, the fact that I struggle to work because I have noise coming from Slack that I'm expected to respond to is NOT my lack of discipline. The person I was responding to just took a fashionable meme on HN which was originally meant for Facebook and mindlessly applied it to Slack. Not applicable.

> I have noise coming from Slack that I'm expected to respond

It's the external expectation to respond that I interpreted as "being a team player as measured by always being on Slack".

Being a team player, broadly defined, isn't incompatible with muting Slack or otherwise managing the noise, and that then comes back to the "discipline" idea. If a person don't mute Slack because they "like" the distractions, then they have a discipline problem, if the organisation doesn't let them mute Slack because a "team player" always responds in three seconds or less, they the organisation has a discipline problem.