system
Given the following post, respond as if you're commenting on Reddit:
human
[General] What valid reasons would post-scarcity civilizations have conflict?

EDIT: I think my base question is: "Do you think conflicts between post-scarcity civs is realistic or simply drama for the sake of good fiction, and why?"

Post-scarcity: have fusion energy or something better, have matter replicators of some sort, bam!: no one needs to ever work again and everyone can have everything they want. This is a prior to my question, so arguing against it is not recommended. On top of that, VR sims of the Matrix / Holodeck / Sword Art Online variety should be endless amusement for most people.

It seems to be rather common that sci-fi universes of Star Trek level tech or higher (or a tier lower) have aliens that are dicks and go around blowing up, enslaving, or just stealing all the resources from a planet. Examples include the Covenant in Halo or the plot of the new (hopefully last) Transformers film where they've decided they need Earth's resources.

I find it completely ridiculous that a civilization would have FTL, energy resources to power space travel, the levels of automation that would likely exist for any civ reaching FTL and fusion-like energy production, etc and think they need to pick on Earth of the habitable planets in the galaxy.

Regarding habitable planets, if Earth is one planet with life forms, and the invading aliens also had a planet, that likely means there are literally millions if not more potentially habitable planets in the galaxy, many of which would be uninhabited. But also, if you can travel here in a space ship, you should be able to set up environments in space, like living on a giant ring or something with all the farmland you need.

This came out sort of ranty, but I think I at least included enough information for a start. Thank you for reading this far.
gpt
>many of which would be uninhabited.

The problem is, most of them aren't. In most Sci-Fi, if a planet has a stable biosphere, it usually has some form of native live that would compete with settlers. 

Still, Post Scarcity does not mean Post Effort. Even with something akin to Replicators, and access to fusion power, something like Terraforming is going to take time, resources and effort. It's a lot easier to just settle an already inhabitable world than it is to make a barren rock habitable. 

And, as stated, since most planets are already inhabited in most Sci-Fi, that leads to conflict.

Then you've also got social conflicts. Just because you don't have resource limitations doesn't mean you aren't still prone to disagreements. Maybe your species abhors slavery, but the one next door embraces it. Or your god doesn't like their god. Or They're white on the right side and you're white on the left side. Post Scarcity just means you don't have to compete over resources, it doesn't mean your ideologies can't compete.