When you imagine orcs, you no doubt picture the ferocious hordes emerging from Mordor in Lord of the Rings, or their variants from any other blasted location which would not appear to be able to support life of any kind. Is there a connection between these environments and orcish nature? Could we begin to understand orc nature as dictated by these circumstances, could we stop thinking of them as inherently evil by nature, and instead simply martial due to their homelands?
If we look to other martial societies that have occurred in our own worlds, we can turn to the Mongolians and the Apache for similar outlooks. These were tribes or bands of people who were forced to subsist on lands that made living hard. These environments were such that they were not able to settle down in great numbers and form large cities, but rather were forced to move constantly in order to keep up with the herds from which they derived their nutrition and wealth. Forced to always move, living precariously between starvation and war, they became warlike so as to be able to raid each other for wealth, to be able to protect themselves from the raiding of others.
If you think about it, there are few warlike societies that come from verdant, rich lands, where the food is easily collected and wealth is abundant. People who grow in these lands turn their minds instead to culture and family, to amassing wealth through work and industry, to trade and civilization. They don't need to risk their lives at war if they can simply work hard and live a good life. It is these societies that the other more warlike ones target.
Thus, when looking at orcs, it makes complete sense to stipulate that their traditional homeland would be mountains or steppes, places where they could not amass great numbers, could not easily acquire wealth, where they would have to be fractious and violent, until, finally united by a leader, they would be able to turn all their violence and energy outward, and destroy the civilized world before them in one great battle.