See, I thought the alien-eating was essential to the story being as good as it was.
I really really enjoyed it, pretty much from the moment of mentioning that the alien's leg was marbled (which implies meat for food) which was mentioned almost right away.
Was it strictly plausible that aliens would keep coming and coming and coming to a planet that just butchers every visitor? Probably not. I would expect, if nothing else, the relatives of some of the aliens would want revenge, and getting revenge on small cluster of population bound to the surface of a planet isn't that hard: grab an asteroid on your way and drop it on them.
But, then again, we don't know alot about what goes on outside. We know that there are many alien races of many varieties, but not what kind of interspecies social structure they have. I get the impression that the aliens who stop by Earth are the younger alien species who have only recently managed interstellar travel and so naively stop by every planet they can reach without shrewdly assessing the risk levels or perhaps willfully accepting that exploration is dangerous but not considering this kind of danger, and who randomly show up on the doorsteps of the first non-starfaring inhabited planets they can find and expecting a fair exchange of higher technology for some more resources for spacefaring. So, these younger starfaring species send explorers, and when those explorers disappear they don't know what happened, and assume they were lost in any of the number of ways explorers can die in unknown territory.
I could see how the older starfaring cultures, once they've developed more reliable travel resources, have met enough alien species so that meeting new ones isn't a grand voyage anymore, have developed self-sustaining ship systems so they don't need outside resources, would avoid planets like Earth. And, even though they know that Earth is a danger to those who stop by, since the Earthlings are planetbound it's only really a danger to those stupid enough to land. Maybe there are so many Earth-like planets with vicious planetbound residents that they don't think it's worth expending the resources to go neutralize the danger. Maybe they figure that anyone stupid enough to land has to deal with the problem themselves, figuring that it's not their responsibility to save everyone from their own poor choices. Maybe they consider Earth a protected ecosystem and want to allow the Earthlings to live or die without their intervention, maybe they're studying Earthlings' behavior from afar and want to see how they treat everyone. I don't know, I'm just saying that with so little visbiility into the outside universe other than that there is kind of absurd number of starfaring races stopping by, one can extrapolate some things.
I also thought it was reasonably well justified why the Earthlings were so quick to eat the aliens anyway, with the described behavior and limited resources. It was squicky and wrong and ew but in a darkly pragmatic way, if you're living on a planet on which you can no longer cultivate sufficient resources to sustain your species existence long-term, then edible foodstuffs from the sky would be a Godsend. At this point they have no long term solution, so whatever they can do to eke out a little bit longer is what they will do. And letting the aliens do what the aliens want to do is just a net depletion of resources from the Earthling's point of view.
What I didn't understand, and I think it was a rather large hole, was why, as Frank Evans asked, the Earthlings don't try to either negotiate a ride off planet, or try to pilot the alien ship off planet. Perhaps because the only kind of voyage that lands is the kind that was stupid enough to depend on finding all the resources including fuel for the return journey on the surface of the planet, and since the Earth is so depleted there is no resources to be had? Maybe?
The borg-like hive mind thingy did seem a little out of place at times, but I thought it worked well enough as a main plot to give a story to go with the setting. The Earthlings are doomed anyway, so maybe the hive mind will have a better time of it, with its singlemindedness. It made enough sense in this particular story that the Earthlings were a trap laid for the stupid but hadn't apparently considered the possibility that an alien species would see through the ruse and rather than avoiding it, would go into the trap prepared to take advantage of it. And I liked the echo of the "we come in peace" trope at the end--in the hive's reasoning, it does come in peace--it gives its host bodies immortality because their minds live on in the collective. All the other races that got eaten also came in peace, but they came in a different kind of peace than this one.
In the end it felt a bit like two stories, but I thought there was enough joining of the two stories to make it work well enough. And the invasive alien species gave enough of a plot so that the eating of all the other species could be setting rather than trying to build a story around that specific part.
I really liked it.