As multiboxers I believe we do operate in that grey area of acceptability. You could interpret this statement any way that fits your bias. Personally I see this being aimed at bots. People use 3rd party tools/plugins for damage meters. They do not condone, and actually will ban people for talking about it in game. As for multiboxing and software input broadcasting: their definitions and applications could change at any point. If you're gun shy because of Blizzard, that's reasonable, but at the end of the day I'm comfortable with multiboxing this game for a few reasons.

1.) Square Enix has a concept of "Service Account" where you can have multiple service accounts under the same Square-Enix Account.
2.) Multiple people have multiboxed this in the past and present. While not popular to do so for a number of reasons, doesn't make it something that's even on their radar.
3.) There is no concept of a token or way to trade in the in game currency for money. As a result, I can't identify any reason why they would crack down on the behavior of multiboxing.

At the end of the day I'm going to enjoy this game (while I can?), do my best to play to the spirit of the game, and be a good actor in their ecosystem. If I get banned or they change their rules, then I'll move on.