No we are not! We are a breed apart. From Antares six, to be precise.
Hahaha! I was thinking proxima centauri. Here to enslave planet earth!
On topic, I think it is due to the natural feeling of jealousy. I mean, if you look at the map, countries which are majority white are usually the richest. Whites led the industrial revolution and are the pioneer of most of the technologies used today by everyone. This is not being racist, but is just a fact.
It is the same reason why people hate Jews/israel ie. due to their disproportional rate of success.
First of all, this prediction is a far-fetched one. Isolationist movement in America is growing day by day with the rise of the Tea party. Tighter controls to immigration in the future is to be expected. Also, previous trend of high birth rates of immigrants won't continue as birth rates tend to fall as incomes rise. Even if one day whites become a "minority", the "majorities" would be people who believe in American values and ideals, so their integrity as a nation wouldn't be affected.
Finally, America (and Russia) isn't as vulnerable as West Europe when it comes to their demographic. At least as far as the threat of radical Islam or any other invading ideology is concerned. Unlike Atheist Europe, Christianity in America (and Russia) is a significant force and there is no religious vacuum there which exists in Europe, as a result of which radical Islam is becoming more and more popular in Europe. This is the reason why Muslims in America tend to be more moderate, well behaved and with higher incomes than those in Europe, a trend which if continued wouldn't be a threat to America.
