Of course their theories were borne out of observations, that's what theories are, a model of our world that fits past observations. When we make an observation that doesn't fit the model, it's surprising because it's by definition unexpected, but it's also an opportunity to update our existing models.

News website tend to focus on the "surprising " word because writers (in this case the PR firm who wrote the press release) have been taught to write "stories" with "characters" who feel "emotions" to engage with the audience, perhaps in a completely opposite way than how researchers themselves describe their discovery in science journals.