I tend to high pass most tracks except for the kick and bass, but it's less about mud down at <100 Hz and more about dynamic range. When you have high amplitude low frequencies (inaudible or not) then the higher frequency content has less head room when stacked on top of that giant wave before it starts clipping. Consider how at the limit, a 0 Hz DC positive offset sounds like nothing but pushes the entire signal closer maximum sample value. In order to avoid that clipping, you have to turn everything down and now the whole track doesn't sound as loud as other comparable music, which is bad news for something you want DJs to play.
There's rarely any useful signal that low for instruments other than kick and bass anyway, so stripping those rumbles and thumps out just keeps the waveform more centered overall. That lets you increase the overall loudness without clipping.
For me, things get muddy when I have too much going on around, I don't know, 100-300 Hz. I high pass tracks to clean up the mud there. Below that, the high passing is mostly for dynamic range and loudness.
There's rarely any useful signal that low for instruments other than kick and bass anyway, so stripping those rumbles and thumps out just keeps the waveform more centered overall. That lets you increase the overall loudness without clipping.
For me, things get muddy when I have too much going on around, I don't know, 100-300 Hz. I high pass tracks to clean up the mud there. Below that, the high passing is mostly for dynamic range and loudness.