I find that I'm not really xenophobic (heck I'm about as pro-let-everyone-who-wants-to-migrate-here-do-so as it gets), but I do wonder if I might be a tad bit more xenophobic if I was in one of those countries that are being flooded with migrants with no history of said mass migration (Norway, for instance).
It's not so much that you hold some disdain for the average migrant that you meet, but rather that you worry the entire culture that's been driving your country/region (Norway was not independent too often over the last few centuries lol) is being upended and replaced almost overnight by migrants. I have a French friend who has become almost uncomfortably anti-migrant for these reasons.
I really don't know how I'd react if I were born in one of those European nations with little real tradition of mass migration... as an American we don't really have a culture based in one ethnicity, though it's definitely fair to say we remain more English than anything. I would think the US might play a role in quelling concerns elsewhere, as it's been shown time and time again that assimilation begins slightly with the first generation, takes hold with the second, and the third winds up almost completely assimilated into native culture.
Seriously, this concern dates back to Benjamin Franklin worrying that the the recent influx of German immigrants would have the US speaking German in a generation or two. The truth is it's generally nations with a strong economy and identity that draws others, and for this reason migrants will usually seek to assimilate their children as soon as possible so as to give them the best chance at succeeding in life.
I'm curious to see what happens with the flood of Islamic migrants into Europe, of course, as there are many who do seem more interested in carving out their own little communities than becoming an integrated part of that tapestry.
Got a little off topic... I suppose I don't find that I'm xenophobic, but I'm not really being challenged in any way that would tempt xenophobia. I have no excuse to even consider such notions, essentially lol