Put it this way: America's founding gentry revered a fictional republic, all marble and civic virtue. They got the truer Rome of massive slave plantations, military demagogues, civil strife and covering up all the many, many problems with pomp and blood-drenched expansion until it collapses inwards
Another important, yet understated reason as to why romanticizing US history in particular is so slimy...
they also look towards surviving works of Roman wealthy opinion columnists complaining about what was ruining the Roman Republic and thinking they have to prevent it from ruining the US Republic, without ever reflecting on what documents survive
this is why I think an education in the classics is actually a key piece of perpetuating fascism