Japan? It has tons of problems: chronically low birth rates, one of the highest suicide rates in the world, extreme workaholism, decades of economic stagnation, and probably the world's most intense forms of social alienation.
https://en.wikipedia.org/wiki/Hikikomori
The latter seems a direct refutation of the alt-right's contention that racial uniformity promotes social engagement and unity. The Japanese are so alienated they barely even have sex anymore. A recent trend in Japanese restaurant design centers around making sure patrons never see another human being, not even a server.
In addition to moral reasons a big reason I can't take the alt-right's racism seriously is that I live in a very racially diverse area (Los Angeles/OC area). Being white I might even be in the minority, or nearly so. My neighbors are more often than not hispanic, asian, or black. Our kids play together, and my daughter's best friends are pretty close to a random sampling of the planet's genetic diversity.
If anything I've found the more recent immigrants to the USA to be more friendly, more socially engaged, harder working, and even more patriotic than multi-generational American natives.
Last year I witnessed the spectacle of a bunch of first and second generation immigrants actually celebrating the Fourth of July. Like really celebrating it. I've seldom seen white Americans genuinely celebrate their country like that. I'd say a good half the white Americans I know are depressed, cynical, and disengaged. This is true on both sides of the usual political divides.
Japan's problem might actually be too much isolation. At the very least some immigration probably would have prevented three decades of economic stagnation.
The neo-racist thesis is bullshit. There is no "white genocide," though there might be a bit of self-inflicted white suicide. Sometimes I think white Americans suffer from the same problems as native Japanese, namely the social diseases that stem from multiple generations of extreme wealth. Wealth promotes social alienation, laziness, a sense of entitlement, and generally taking things for granted.
I've long wondered if the cycle of civilizational rise and fall is caused by wealth. Civilizations rise on a tide of innovation, cooperation, and optimism, but then they get rich and succumb to the social diseases that result from wealth and power.
Edit: Yes there are racially segregated high-crime ghettoes in the LA/OC area, but this seems to happen when you have racial isolation combined with poverty and criminal enterprises like illegal drug trafficking. The entire metro area is incredibly diverse and the majority of it is pretty safe. The area I live in is extremely diverse and has among the lowest crime rates in the state.
Edit #2: If I didn't live in the USA I'd probably want to live in the Netherlands, Germany, Australia, New Zealand, or Canada. I'd like to add the UK too since I love a lot of their culture, but the UK's government seems just as insane and dysfunctional as ours.