The reason those comments get downvoted is because they are wrong. Anyone writing off slack as an IRC clone exhibits a very poor understanding of either system. Slack is similar to IRC in that they deliver text-based communication, but that's about it. The underlying protocols, features, and so forth are radically different.

Most anti-systemd comments are similarly poorly thought out and articulated.

This might be superficially usenet+crypto, but oftentimes things are more than the sum of their conceptual parents.