Yes, refugees bring baggage. But we weren't talking about "baggage" (which is a whole other discussion; suffice to say, I think it's probably a less broadly-applicable truth than generally assumed, and is exacerbated in kind by the attitude towards refugees just by their nature as refugees). No, I want to know the sort of baggage that can be labeled treachery, terrorism, and horrors, as you do above. When have we seen Ala Mhigan refugees (who aren't Ilberd or the Corpse Brigade) engage in this behaviour?
As for the Domans: you see the difference, don't you? The Doman refugees were granted shelter and work, treated with dignity as people first and foremost; the Ala Mhigan refugees were treated as a blight, an invasion, as little more than a nuisance and a menace (whether they'd actually done anything menacing or not). The reason that the Domans got this treatment is complicated, of course - they were significantly less in number, for one (although the charity they got STILL required intervention on the Scions' part) - but that just hammers the point home: the behaviour of the two groups can't be compared, having gotten such vastly different reception, and it thus can't be attributed to culture or nationality.