Grist: Imagine if people started selling their shares of Berkshire Hathaway, the biggest corporate conglomerate in the U.S., because it owned a company that invested in coal-fired power plants. It sounds improbable right? Pull money out of a successful parent company just because one of their subsidiaries was acting badly? Its just not the way the world usually works. But thats about what the Norwegian Pension Fund the wealthiest sovereign fund in the world, which controls $870 billion just did...