A professional what? Reviewer? Journalist? Blogger? The face of a company/site. I'm speaking more of his actions as a human being (harassing women, making sexist comments, being a general asshole to people, not being able to take criticism without throwing a fit, etc.) I've never read any of his reviews, the only thing I ever read was some really stupid article about "strong female characters who weren't sexually attractive", and threw in a dinosaur from primal rage and other such ridiculousness. I assume he was trying to make some point about feminism or how gamers view feminism or whatever, but he really just came off as a douche.
He just rubs me the wrong way as a human being and someone who represents a site. It's similar to back in the HealingTouch days, when we were labeled as anti-ScrewAttack due to our community and how some of the faces of our community behaved publically regarding the whole split. Jim Sterling just does a terrible job presenting himself as one of, if not THE face of Destructoid.