I mean, the hitler comparison falls off with those specific examples, but I get that you’re saying.

First, they were successful for the most part.

Second, it is the far past. The distance in time means that most people will only ever know about the biggest brush strokes of their biography and actions. The records of the eras aren’t exactly rife with full detail for every bit of their lives. And what is there, most people encounter at the superficial level of a high school world history class.

That kind of class isn’t geared towards detail, nuance, or moral judgement. It’s about the overview.

Since all of the ones you listed are also pretty damn interesting, and made major impacts to human society (for good or ill, that’s not the point of the answer to the question as asked). This in turn means that they’re memorable compared to some random king or emperor that was just doing their job and running their nation without trouble.

In other words, they aren’t boring. And, tbh, they weren’t fascists. They never had that level of complexity to their goals. Fascist != dictator by default. That part means that until and unless you start looking at the horrible things they did, there’s no convenient modern label to apply to them in a general history class to point to them not being good people.

Remember, most entry level history classes might have a week to cover the entirety of the Roman Empire; devoting time to Caesar’s nastiness just isn’t relevant to the goal of that kind of class. The only reason he’s worth going into any detail about at all is that he changed Rome to such a degree that it’s a pivot point, and cant be entirely skipped like the majority of historical roman leaders.

From there to “glorification” is a matter of fiction. We don’t have the kind of detail that allows for interesting documentaries, so what we get outside of advanced history classes (which people won’t likely take unless they’re intending to be historians) is infotainment and outright fiction using the names of people. Once you start making books and shows and movies, entertainment and profit are the goals, not historical accuracy or even adhering to actual facts at all. Most of what people think of about Caesar is from Shakespeare.

So you then have people with disjointed and filtered ideas about historical figures, mashed together from a few facts and a lot of fiction.

Honestly, even with more recent figures, you run into the same thing. How many people do you think could give a detailed and accurate biography of either president Roosevelt? Or JFK? Or Regan? Man, there’s people that couldn’t tell you anything about the current world leaders beyond their name.