Well, there are a couple of things that apply here.
Firstly, Human Evolution is a sexy profession among the sciences. There is a lot of competition to be the person who discovers a new human species. For example, consider Donald Johansen, whose entire career has been based on the discovery of Lucy. That made him world-famous and generated more research funds. Today, he is the head of a research institute, the Institute of Human Origins.
And a lot of the way that human fossils are interpreted has historically been influenced by people’s attitudes and expectations. When the first Neanderthal fossils were discovered, there was a significant number of people who insisted these must have been people who were diseased. Likewise, the Piltdown hoax worked for as long as it did because it fit people’s preconceptions about what a human ancestor should look like.
So, when an unusual fossil is discovered, there is a lot of motivation for the discoverer to see it as a new species. Other scientists will likely be more sceptical and there will be debate for some time to come. Settling of the debate will probably require more evidence. It will be interesting to see if DNA evidence can shed any light.
As far as the behavioral characteristics attributed to the new fossil, red ochre has long been associated with burial rituals, and the bones do seem to show evidence of having been broken for their marrow. But I am skeptical that this means they were dinner for another human species. How often do you ritually bury the leftovers of your dinner? I suspect there is another dynamic involved. Possibly a ritual consuming of the dead by friends or relatives in order to assume his/her attributes?
I don’t see where there is any data to support the ideas that modern humans mated with this supposedly new species and used their bones as tools. Again, these two behaviors seem to me to be at odds with each other.
Dr. Curnoe seems IMHO to be extrapolating too much from a small amount of data. This would be motivated by the natural desire to be the discoverer of a sexy new species.