Intermodulation in this case is distortion that wasn't in the source material. It's a product of the failings of the playback system to perfectly recreate high frequencies without distorting the lower ones, and will vary depending on which system it is played on.

Certainly some people find certain kinds of distortion pleasant, but the people arguing for 192kHz claim increased fidelity, not pleasing distortion - when it is just the opposite for any stereo that introduces these artefacts.