Maybe they shouldn't expect people to answer Slack messages 24/7, and this would subside.

That could be easily fixed by doing meetings better. Have fewer, shorter, more focused ones.

Most of the issues cited in this story could be addressed by not having "a meeting where an email would suffice" and by not inviting everybody and their cousin to every meeting for "optics" to to play political games. Just invite the people who are actually needed to make a decision. If you're not there to make a decision, it probably doesn't need to be a meeting.