Maybe we think why blogs were created in the first Place. Usually, blogs were written to be an outlet of the author's mind or to cater a particular audience. It has specific target readers and these are those people interested or under that topic.
People read on things that they are interested at and to those that they can relate to. And I think that's is the difference between news blogs and the other blogs: target audience.
Other blogs are meant for a particular group of people. For example, writers write blogs about marketing to target the businessmen or entrepreneurs. There is a little chance that a person not interested in marketing will read about it.
While news blogs attracts the attention of most people because its target readers is the society itself. It is meant to be fed to the general public. People read what is intended for them and what they can relate to, just like blogs about their own community. Another is the popularity of the topic. Usually news blogs are updated and trendy.
I hope this helped!