This may seem like a petty point, but the headline of this story goes a long way toward explaining what's wrong with the way the media, and therefore much of the public, perceives scientific discovery and conclusion. Science, but its very nature, is a process of elimination. The scientific method eliminates possible causes for a given phenomenon. What scientists have done here is eliminated every possibility known to man, other than an asteroid strike for the demise of the dinosaurs.
That makes it the most likely cause, based on the information we have today. But outside of developing time travel, we'll never be able to be definitive in any declaration about what killed the dinosaurs! The reality is science just doesn't work that way. Science becomes definitive when you can replicate; I can boil a thousand different pots of water and if the boiling point is 212 degrees F and 100 degrees C every time, we can establish that's the boiling point of water.
There usually isn't enough evidence to apply that scientific method in that fashion to the ancient past and it's entirely impossible to apply it in the fashion to the future (global warming). There is nothing "official" about this finding. Scientists simply feel more comfortable in the "consensus" belief about what killed the dinosaurs. In other words, there is nothing new here.