Many bloggers are lazy.
The flip side of the huge army of bloggers overlooking mounds of data is that many of the aren't really reading, understanding, and forming coherent opinions on the topic. They are skimmers. Most of them are just looking for stuff that matches their own biases--the internet is a sort of arms bazaar for those people, where they can go from table to table gearing up for the fight.
The problem (among many) is that these are the self-appointed "new news" people. And on complicated issues like climate change, health care, and the economy skimming for sound bites is a huge disservice all around.
I don't have an answer here, BTW. I'm just sayin'.