Since your pro friends probably use Canon/Nikon they might be quick to blame the camera.
I guess that 'noise at 100%' means when you zoom in to a 100% view of an image, and if I did that I would expect to see noise at ISO 800 onwards from most APS-C digital cameras, except for the latest crop - K5 for example. It comes along with those as well, just at a higher ISO.
I did find some on-line tests of the K-r and none of them mention noise as a problem - indeed several say it's a low noise camera. These are the first four I looked at, there was another one that was hanging:
Pentax K-r Digital SLR Review Pentax K-r review (with DAL 18-55mm) | Expert Reviews Pentax K-r Review | Digital Camera Resource Page Hands-on Report: Pentax K-r DSLR camera review | Camera Gear Guide
So, either you have a dud or it is something to do with either how you are processing the images, and/or your expectations.
You have posted some iamges.
The first one that had EXIF was shot at ISO 800 and looked to be massively oversharpened - there are obvious halos round the twigs in the bottom RH corner. With that amount of sharpening it's not possible to see what the original image quality is like.
The second one was shot in poor light at ISO 6400, f4, 1/15, and it's no surprise it shows some digital noise.
We haven't seen one taken outside, in decent light, at ISO 200, on auto, with all the settings at normal values e.g. trawl through the menus and make sure settings are set to normal, especially the ones to do with noise reduction and sharpening.
Quote: I was trying to reproduce what I was seeing but not capturing
I really don't understand this.
FWIW I was able to make reasonable A4 prints from a Fuji camera with a similar number of pixels to the K100D. It was a cheap and nasty camera that produced awfully soft RAW images (or horribly oversharpened JPG ones), but with shooting RAW and some careful PP a few of them were OK and did well at the camera club. Apart from producing innately better image quality (better glass, better sensors, better camera software) images, the one thing the extra pixels in it's replacements have let me do is more dramatic cropping.