Every family in the world uses IM, and Slack isn't very different from any of the hundred other options out there for group messaging. So not too surprising that families are using it.
Similarly all the other software mentioned can be used for simple calendaring, TODO lists, reminders etc., all of which most people here undoubtedly use in some form to manage their life. It's just the association of these brands with "work" that has people going WTF.
That’s not realistic, messengers are much more ubiquitous than any other kind of software and are mostly used in a family/friends network. We had our local digital festival last week an we had school classes teaching seniors WhatsApp.
I've no idea what the GP commentor is talking about. I don't know of many families that use messaging apps. Yeah, texts, a bit, but most of the families around me don't do this. Heck, most of the kids don't have cell phones until they get into HS, and event then, the phones are banned during the school day.
Similarly all the other software mentioned can be used for simple calendaring, TODO lists, reminders etc., all of which most people here undoubtedly use in some form to manage their life. It's just the association of these brands with "work" that has people going WTF.