If the target were industry executives and product designers then, yes, getting accurate information on new products from competitors and the industry would be important but this is not the case.
The target market is, instead, eager-beaver fans who are bored at work or home and want something to entertain them and they find video game news and rumours entertaining. I've been part of that crowd in the past. To put it bluntly, I'd rather tons of inaccurate information constantly streaming into my RSS reader than one or two accurate updates a month.
This is a simple case of the market shaping the product. I wouldn't be so quick to attack the "journalists" who are simply giving their readers what they want.
Complaining that gaming news is not validated is about equivalent to complaining that the National Enquirer isn't top-rate journalism. We know and that's not the point.