That's not a very good headline for this NYT article. The article is not about the complete rejection of blogging interns, but about how young people who are at ease with blogging need to learn that the organization is unlikely to accept it if you use your inside information for blog material.
Haven't writers always exploited the knowledge they've gained from access to things other people don't know about? It's the way of the writer, isn't it? The difference with blogging is that you publish your writing instantly, using information you just came across. That's what gets you fired. And it's not just about the workplace. Writers also exploit their personal relationships and use the secret info they get from having friends and lovers. Blogging's got to be riskier here as well, because you don't have the time lag and the elaborate processing of the material.