Amazon CEO Andy Jassy on Thursday took aim at regulators who are increasingly blocking mergers, including the company's planned acquisition of robotic vacuum maker iRobot, which fell apart earlier this year amid antitrust concerns."I think it's really kind of a sad story," Jassy said in an interview with CNBC's Andrew Ross Sorkin on "Squawk Box" after the Amazon chief released his annual shareholder letter. The acquisition stood to give iRobot a competitive boost against rivals, Jassy said, but ...