This column was originally published on RealMoney on July 31 at 11:04 a.m. EDT. It's being republished as a bonus for TheStreet.com readers.I was shocked to read analysts and traders defending Rackable Systems ( RACK) during its post-earnings death plunge Friday. A few respected commentators, including RealMoney's Bob Faulkner, even told readers they were adding to current positions. I strongly disagree with the idea that the torrid session was a buying opportunity in any way, shape or form. The decision to buy more stock implies that Friday's selloff was the best possible time to take on added risk in this demolished issue. I believe the stock is headed lower, and will continue to do so for months or years to come. Of course, there will be bounces along the way, and even a countertrend rally to squeeze overeager short-sellers. That isn't what I'm talking about here. Those who pounded the tables last week are long-term players, not short-term opportunists, so they must believe the stock will trade higher in 2007. That's a very poor bet, in my opinion. Here are 10 reasons why Rackable Systems isn't a buy now, by any stretch of the imagination.