If someone concludes that it's fine for them to eat cows because cows never invented computers, then there's not really much of an argument against aliens turning us into meat slurry because they have the 4-chambered quantum brains needed to invent hyperdrive and we don't, is there?
Liberal assumption is that our world is the best possible one. So we have to assume that it is a war of all against all.
However without the civilizing effects of capitlaism we would return to our wild nature and have a world where everyone is struggling against everyone else all the time.
So aliens beinf more advanced would have to be more like us as we are perfect.