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Even today, humans (who are a long way from being able to make sporting trips to other star systems) dont rely on predation much. We farm our food, and soon well manufacture it. Killing just for the fun of it, as the Predators do, is no longer considered socially acceptable in most circles. Real Predators, who must be many thousands of years ahead of us, have presumably moved beyond this.

I don't agree, I don't see any evidence that humans are any more socially advanced than the Greeks or Romans of 2000 years ago... humans wear a thin veneer of civilization, imposed by the culture they develop in.
Scratch the surface and the club wielding man-ape is still alive and well... just achieving the technology to travel across space won't change that, and I don't believe it would effect other species either.
In fact if you think about it, space travel might make matters worse, every planet that was colonized would soon begin to diverge socially from the others, the colonists would eventually evolve as well, after millions of years the parent species could have many genetically linked but possibly physically dissimilar branches...
how might the ‘pure’ old world galactic citizen look upon the socially backward colonial cousin? If these were human’s the answer is simple, they would be looked down on, leading to resentment and perhaps to conflict...
Just wondering, how much resources would a galactic civilization consume? I’d think a system would be used up pretty quickly building super cities and fleets of ships, if matter replication is possible that would help I suppose, just grind up some minor moons and asteroids for raw material, and recycle everything...