Its quite intuitive that tires have maximum pressure figure - inflate it more and something could explode. Furthermore, it is common knowledge that under-inflated tires result in snake bites.
What puzzles me is that all tires indicate minimum pressure.
This could be somewhat justified about DH tires, which tend to be produced with thick sidewalls and thick soft thread pattern, resulting in reduced pinch flats (among other advantages). However, on different cross-country tires I have seen minimum pressures from below 2bar to 2.7bar at least. Is this just marketing or does the number mean anything?
Furthermore, how can the manufacturer know what the riding terrain and rider's style is? In my opinion those affect chosen tire pressure a lot more than sidewall thickness.