Why isn't it good? Ethnocentricism provides meaning and purpose which is sorely lacking in our relativist, globalist society.

Relativism merely the philosophical tolerance for doubt, which is the beginning of wisdom. Moral absolutism is an escape hatch for people who don't like doing the hard work of thinking.

Ethnocentrism certainly provides some meaning and purpose, but it's a shitty purpose of 'my interests at the expense of those other horrible people' and almost invariably ends in atrocities.

Globalism is simply a function of technological advancement, which is not going to go into reverse. We are not giving up instantaneous communications, or high-efficiency containerized shipping, or air travel, or GPS, or any of that other good stuff, despite the urgings of people like Aleksander Dugin.

You can have both a globalized society and meaning and purpose: there's a whole cosmos out there waiting to be explored, and the idea that there's more meaning to be had in militarizing the marginal differences between different ethnic groups is bizarre to me.

Because it's something that evolved for small unsophisticated groups, not for societies with billions of people with nuclear weapons.

Probably we all can think of a lot of instinctive behaviours that are a bad idea in what, now, are our normal contexts and that we avoid in a daily basis.

Intelligence, unlike evolution, is not blind (or, at least, no so blind).

Well one thing you can always say about nazis is that they had a meaning and purpose.