This is typical scientific language, and the fact that the article uses this kind of language shows that its author took care to communicate the actual science.
Scientists, when talking about their results, especially new results that have not been corroborated by other studies, are very careful to acknowledge that their interpretation of the data might be incorrect, or that they might have overlooked something which would change their conclusions.
When you see scientists proclaiming that everything they say is absolute truth and that there is no other explanation, then it is time to be suspicious. They're probably pushing an agenda. (Think: global warming. No uncertainty is ever expressed by those promoting the notion of anthropogenic global warming.)
Okay. I think I had a little too much coffee and studying today.