Until Blizzard says otherwise my interpretation focuses on the last paragraph which seems to indicate specifically what they felt was over the line in ClassicLFG which states:
Since the problem seems to be, “an interconnected social network that relies on other players also using that same add-on,” it would seem they would focus on breaking the addon to addon communication or possibly limit it to guilds/raid/party as someone in another thread mentioned was how the addon communication channels originally were (not sure if that’s accurate).
The chat parsing and posting part would seem to fall under “presenting information or providing aesthetic customization.”
Limiting addon to addon communication to only party/raid/guild members or breaking it entirely would seem like it would break a lot of other random addons but I don’t see how they could target the “interconnected social network that relies on other players using that same add-on” in any other way.