I think that warning is just geared towards "dumb" PoE sources, and perhaps they just don't want to have to explain the difference; standard PoE (802.3af/at and whatever else there may be) ones will negotiate power with the receiving device. That's the only official word I've seen on it, and it doesn't say that much, but a community member reports that they heard from Support that this is, indeed, the case:
It should still be noted that the hub doesn't actually support PoE, so you'd still need some adapter to make that work if your goal is to actually power the hub (I don't think yours is, but just mentioning since I'm sure someone else will find this by search). I have seen some mention that staff have seen some hub failures from that:
So, might not be a good idea to do that. 
(Which is pretty much the only way you can.) But it looks like just connecting it to such a port should be OK, as long as it's a standard/negotiating setup.
