If you can traverse interstellar space you are pretty much required to "live off the land" as you go and especially so once you reach your destination. This mea

If you can traverse interstellar space you are pretty much required to "live off the land" as you go and especially so once you reach your destination. This means you possess the ability to produce all of the energy, food, material, etc. required for a civilization to exist from what is present in either interstellar space or a solar system. If we put our sci-fi hats on we can imagine a perfect system of recycling and matter conversion that can keep a massive generational ship functioning with the only input being hydrogen scooped from the space it crosses. If you possess that level of sophistication then you really could live anywhere. That gives you plenty of living space with little motivation to pre-emptively attack others.