Because do you really think those samples are properly exposed? A great camera cannot compensate for poor photography.Instead of bashing could you please keep your mouth shut. I tried to be polite before but I am losing my temper. Or t least think before you type. I don't have the right to have a dark underexposed looking image? The shadows should be clean in such situation. I didn't want criticism regarding my images or my technique I just wanted to figure out the noise issue.
Actually, whether or not the image is underexposed is extremely pertinent (I don't know whether yours is or not). If you underexpose (either accidentally, deliberately or as a result of using HTP), then noise will be significantly higher. Each time you increase exposure by a stop in post, you double the amount of noise. It's a matter of physics, regardless of how much or little noise the sensor captures to start with. Also, as others have said, the early versions of Lightroom after a camera release have a tendency to process images sub-optimally. For example, when I first got my 7D, the images looked soft with double exposure-like effects on the transitions between very dark and very light areas (such as the black and white feathers of oystercatchers). Upgrading from LR2 to LR3 mostly resolved the issue.
In order to test whether it is a sensor issue, you need to make sure you expose correctly (I actually tend to err on the side of slight overexposure to minimise noise), with HTP switched off and processed by both LR and DPP. It is the only way you can be sure it isn't a problem with the sensor.