These people come to a conclusion and call it a scientific fact. It is still a conclusion and theory. There are many theories and conclusions. DNA form one bone can not prove much but it causes a jump to a lot of conclusions.
More data please and peer review.
Hey, it worked for the 'Global Warming' guys over in the Meteorology Department! We need more funding, too!......................Maybe we could call it 'DNA Change'...............................
In scientific terms, a "fact" is a confirmed observation, while a "theory" is a confirmed hypothesis = explanation.
So, for examples, fossils and DNA are facts, while evolution and out-of-Africa are theories.
Barring some error in measurements, you don't expect facts to ever change, but theories can and often do change as new facts become known.
In this particular example, the new fact is DNA retrieved from very ancient bone, but everything explaining what it all means is based on theory -- i.e., radiometric dating, evolution, ancient pre-human migrations & interbreeding.
The new facts tend to confirm "out of Africa" theories, while providing possible dates for human-Neanderthal interbreeding.
But if you were hoping to find metaphysical or religious certainty in such science theories, then your expectations were highly unrealistic.