Sparta, the Third Reich, the French Revolution, Chattel America, the British Raj.

My point here is that a lack of a central government will naturally lead to some sort of central government establishing itself. It could come from inside or from an external threat. It's possibly that that government turns out to be authoritarian and oppressive, like the ones I mentioned.

For instance, how would an anarchist ethnically Jewish society hold out against an industrial Nazi Germany should they be so unlucky to simply exist next to them?

The British Raj managed to establish itself and rape India for 90 years even despite there already being established governments in the region. Imagine how powerless an anarchic Indian society would've been to defend against the British Empire at it's peak.

Anarchy is not sustainable. That's why we should strive to put in place a good and equitable government to protect us from that possible tyranny. The problem is the same human forces corrupt government's too.