I can easily demonstrate with the example files from http://www.gballard.net/photoshop/pdi_download/ if you download this zip http://www.gballard.net/dl/PDI_Target_Folder.zip you will get a folder with many different tagged versions of the same test file. Included is PDI_Target_WhackedRGB.jpg that has crazy colours with an associated profile that will fix the crazy colours. This allows us to easily see the issue.
Here's a screenshot of the thumbnails for the high res test images from that zip:
What should happen is opening any of these images will show the test image as normal as the embedded ICC profile will load to 'correct' the colour. What actually happens if you double click the purple PDI_Target_WhackedRGB.jpg image is that XnView opens and shows a purple image. i.e. it's not actually loading the ICC profile embedded inside.
What is stranger however is that if you then scroll through the folder of image and back to the PDI_Target_WhackedRGB.jpg it will show correctly. Likewise if you open another image and scroll to the whacked image it will show correctly. This suggests the XnView does load the ICC profiles, just not on the initial image you've opened the program with.
I've made a little video to demonstrate. Keep an eye on the colours as well as the file name in the middle of the test image. At the end I show how a regular image would could look desaturated if directly opened, the actual effect of course depends on the profile that is embedded.
You can download the video here https://dl.dropboxusercontent.com/u/100 ... -Issue.mov
I hope this helps explain the issue XnView has with ICC profiles on OSX and a resolution can be found. Feel free to ask any questions. It's really superb software, I hope it's an easy fix.