Right. But the idea that tech blogs should stick to tech stuff isn't. People categorize information because it helps them manage the information overload of their daily lives. I go to tech sites to read about tech things. When I want politics, if ever, I go to a political site. When I want entertainment news, if ever, I go to an entertainment website.
That is only one way to look at it. Another viewpoint is that a website should cater its content to what its audience is interested in. In the case of Tech blogs, their audience is predominately techies, interested in the latest gadget and such. However, techies are also interested in major events. If the world is going to end tomorrow, I want to see that announcement on slashdot, gizmodo, engadget, and every other tech blog.