My guess, probably because they’re idiots.

“ A lightweight, standard publish/subscribe mechanism should be identified; possibly something like MQTT (which would have the added benefit of allowing for network-wide communication). In the meantime, the use of D-Bus as a legacy technology may be acceptable (even though it is considered obscure, convoluted, and closely linked with various other Red Hat technologies.”

This sort of sums it up right there. I mean I think dbus is a trash fire, but not because it is tied to RedHat, and “something something” hand wavy MQTT isn’t a real solution.

This seems to be more of a project driven by Linux hate then actual design principals. The former is not so much a problem as the latter