I don't see why people keep conflating "advanced" technological civilizations with civilizations that happen to be "advanced" within the bounds of that particular person's individual moral worldview.

These are not the same things and "advancing" on one axis does not require "advancing" on the other axis, even taking into account the fact that beyond a certain point, one person's moral viewpoints are not necessarily universalizable in the Kantian sense.

Presumably because that's been our experience with human societies? You might protest Germany in the 1930s was "modern" technologically but still "barbaric" morally - but I think that overlooks the way all the European powers were behaving in Africa and Asia, barbarism wasn't so uncommon as all that. And it's less common now, even as we've made more technical advancements? I don't think we develop on all axes in lockstep, but there's still a general trend, and I'd be pretty surprised to find aliens advanced enough to come visit who didn't already have plenty of resources, so why bother messing with us?