Italian fascists did have fashion forward uniforms.

So did the German Nazis back then now I think about it.

Maybe there is something with cult-like thinking, fascist or not, where the aesthetics seduces more people into wanting to be a part of it all?

No doubt the smart uniforms, the rallies, the flags, the songs etc were a factor in many young men joining the SS.

There's a bit of writing in that direction if you're curious. I like Benjamin quite a but and have gotten a lot out of his thinking. Here's the wiki-level entry to it:

https://en.wikipedia.org/wiki/Aestheticization_of_politics

Oh, it was 100% marketing.

It's not just fascists, either; totalitarian regimes _in general_ tend to be very keen on this sort of thing.

They like purity. Purity of the body (fitness and lifestyle) and purity of society (regimentation, conformity, single race, single ideology, single sexuality, standardized architecture).

It's neurological. They feel emotional disgust if the regimentation isn't there.