I will stick my oar in on this and say that whenever you go abroad, people will always try and find out other people of their own nationalities. David I understand what u're saying but look at it this way - in terms of jobs, I don't think it's got much to do with living standards back home (I;m western and I have a lame salary so I don't think it's got much to do with nationality - but hey why should I complain? Back home in England right now, there aren't too many worthwhile jobs going)
I have a slight issue with what you're saying about the living standards issue - pardon me but we arent in our native countries when we are in Qatar. Living standards here are different. Different people may have different expectations, but from the perspective of an Indian or a Fillipino what they earn here is going to be much better than what they get at home (and think about it, tax free income is going to sound pretty tempting to Westerners like u and me)
Also I was wandering, maybe when these people advertise for same nationality in their accommodation - don't u think it's a matter of comfort? Supposing they wish to share accommodation with people of the same nationality who they know would understand them and understand their habits? Surely even u, in all u're educatedness and worldliness, would understand that when it comes around to personal space, people get enourmously finikity??????