The lack of organizational structure for such militias formed by the anarchists and lack of authority mean though that a conspiracy to destroy the anarchist society will always be infinitely many steps ahead of the response of said society.

Furthermore, what stops the ~30% of people (whether nazi Germany or DJT, that's usually the percentage of votes recieved for right wing radicals) that will almost definitely not be interested in keeping the anarchist society functioning from attaining weapons and having their way? Even ignoring the historic context, tribalism seems baked into the human existence, how is that nullified?

Further, people will always be fearful, so it's great to say "their fellow anarchists would take up arms" but how many are truly willing to do that? Revolutions would be much more common if they were.

That's why I think there's significant cultural/educational changes needed before such a society (or something similar) could be attained.

I think it works great on a local level in small communities, but we have a globalized world, for better or worse, and have greatly outgrown the small communities in which such a philosophy would be most effective imo.