The most important is also the shortest, because by this point you either agree or disagree.
The Cat Fanciers had an ideology. It’s not hard to find. They had a philosophy, too. Nobody’s ever heard of Giovanni Gentile, and you might want to ask yourself why not, but it doesn’t matter. The point is, there was enough intellectual heft behind Cat Fancy that even serious, heavyweight people could buy into it, in full public view. The Black Cat Militia — the fanciest Cat Fanciers of all — was full of professors, doctors, lawyers, industrialists; far from mindless thugs, they were better educated than average, with better degrees (up to and including PhDs in real subjects) the higher up the ranks one went.
[If it helps, think of how many serious, heavyweight people were in the Freemasons, well into the 20th century. Did they believe all the ooga-booga stuff about Masonic ritual extending back to the time of the Pharaohs? Of course not, but they took the ritual aspects seriously, because whatever else it was (and is), Freemasonry is a brotherhood. Brotherhoods depend on ritual. So did your average obersturmbannfuhrer really believe all that junk about World Ice Theory, Atlantis, the power of Norse runes, etc.? I really doubt it. But the “brotherhood” part? Oh yes; to the bitter end].
What really held them together, though, was an aesthetic. A vision. The only reason the Cat Fanciers’ techno-anarcho-retro-futurism seems weird to us is the same reason nobody’s heard of Giovanni Gentile (or Ishiwara Kanji and the kokutai): They lost the war. It’s no weirder than Karl Marx’s techno-anarcho-retro-futurism, and the only reason “Marxist” isn’t a swear word right now is because the same professors and media figures who were so hot and bothered for Cat Fancy (esp. the Italian variant) switched sides once it became obvious how the war was going to turn out. Stalin’s crimes dwarf Mustache Guy’s by an order of magnitude (and Mao has Uncle Joe beat by a country mile), but wild horses still couldn’t drag an admission out of most “educated” people that mass murder is a feature, not a bug, in the ideology.
For a modern techno-anarcho-retro-futuro thing, I suggest mythologizing the Fifites (already mostly done, I realize), combined with end-of-the-Empire conservationist paranoia:
The light really is dying, comrades, all over the former West. The glories of belief, of science, of the very concepts “logic” and “reason,” are being pushed back into darkness, not just by the Marching Morons, but by smart people who owe everything in their lives to Western Civ. These “people” — decadent and corrupt enough to make an Ottoman pasha blush — would rather see the whole world burn than endure the tedium of their sheltered, cossetted little lives one second longer.
Resist them, or die in a nuclear fire. Why on earth do you think they’re so desperate to arm the Iranian mullahs? It serves no geostrategic purpose. It’s guaranteed to destabilize the region, and that, comrades, is the entire point. If they can’t goad us into a war with Russia over Syria, then give nukes to the mullahs. They’ll use them — you know it, I know it, Obama and Hillary and Soros and John Kerry and John McCain and every faceless bureaucrat at the EU knows it. Bibi Netanyahu certainly knows it, which is why they’ll strike first, and the SJWs can crow about it for the 59.3 seconds it’ll take between that and the arrival of Russian / Chinese ICBMs in our skies. They’ll die, too, but at least they’ll die smug — to the SJW, that’s ultimate victory.
Rage, comrades, rage against the dying of the light. If you can’t fight — and not all of us can — preserve. Be an Irish monk in the Dark Ages, hoarding up humanity’s precious inheritance against the possibility, however remote, that we might crawl out of the caves again. But if you can, fight! The human race depends on it.*