Attacking nationalism

Libertarian economist Bryan Caplan writes:

White nationalism is one of the most reviled ideologies on earth.  But what exactly is so awful about it?  Menachem Rosensaft's piece in Slate quotes some leading white nationalists, but never really explains why this nationalism is worse than all other nationalisms. 

As you'd expect, white nationalists dominate Rosensaft's comments.  Several point out that he's is a staunch Zionist, and quip, "Nationalism for me but not for thee."  I'm a staunch anti-nationalist, ...

Apparently a lot of Jews prefer to identify as non-whites, and to promote their own ethnic interests over those of non-Jewish white groups. As Caplan explains, they are just showing in-group loyalty. Rosensaft quotes an explanation for why he favors in-group loyalty for his fellow Jews but not other groups:

Jewish activity collectively, throughout history, is best understood as an elaborate and highly successful group competitive strategy directed against neighboring peoples and host societies. The objective has been control of economic resources and political power. One example: overwhelming Jewish support for non-traditional immigration, which has the effect of weakening America's historic white majority.

Caplan may not be Jewish, but he does advocate a libertarian open immigration in order to destroy nationalism. He continues:

After all, white-majority countries still have greater military power than all other countries combined. ...

So how bad is white nationalism? Back when white nationalism was popular, its sins were massive, but hardly unique. The doctrine currently does little harm because it's so rare. If however white nationalism regained popularity, it would be a cataclysmic disaster because white-majority countries have the firepower to wreck the havoc other nationalist movements can only fantasize about.

I am not sure about the terminology here. Every country in the world is nationalistic. It is not clear how the world could function without nationalism.

I don't know why anyone would call the Nazis white nationalists. They were German nationalists. If you are going to lump together majority-white countries, it seems to me that they are some of the least nationalist countries, as many of them allow large immigration from other ethnic groups. Furthermore, the European and American countries have long histories of making the world a better place.

Caplan's main argument is that in-group bias is a human failing. This is about like saying that love is a human failing. Most, if not all, humans have in-group biases. He complains that a Chinese leader sides with the Chinese, but what else does he expect?

Even if Caplan could somehow persuade everyone in the world to treat the interests of others equally, how would that work? How could we have representative democracy, unless the representatives can favor their constituents? How could we have capitalism, unless the board of directors can favor the stockholders?

These arguments against nationalism just boil down to Rosensaft and Caplan not liking the nationalism of other groups.