Strange historical revisionism of ancient Rome

While not enormously popular, and at this point in time still pretty fringe, there's nevertheless a small section of the modern far left that, for some reason, wants to depict ancient Rome as, essentially, this multicultural paradise, a melting pot of different cultures and races, where diversity was embraced and welcomed, with people of all kinds of ethnicities, races and nationalities were accepted and even got to high positions of power. A perfect example of "diversity is strength". 

However, we know from history that in reality ancient Rome was not like that at all. In reality ancient Rome did not only embrace expansionism and colonialism, but did so in the most brutal of ways. Ancient Rome did not embrace diversity: They conquered and subjugated peoples by brutal force. Rome was not "diverse" because they embraced and welcomed people of all creeds and colors: They conquered nations, subjugated them, took them as slaves, and demanded tribute and absolute obedience. Any sign of rebellion or dissent was brutally squashed by military force, with very little qualms about it.

Ancient Rome was not some kind of multicultural melting pot paradise: It was highly structured, with Romans being the highest class, and everybody else being below them, as subservient and even slave classes.

In other words, Rome was imperialism at its worst.

In summary, ancient Rome:

1. Embraced brutal expansionism and colonialism.
2. Conquered and subjugated peoples and nations via sheer military force.
3. Forced those subjugated nations into submission, into paying tribute and taxes to the Roman Empire.
4. Engaged in massive amounts of slavery, most of them from among the peoples they had conquered.
5. Engaged in extreme enforcement of their authority, brutally squashing any rebellions and dissent via sheer military force and extreme punishment.
6. Was a highly stratified society with native Romans at the top. Other peoples were considered much lesser.
7. Romans were prejudiced against all people who didn't look like typical Romans. (And yes, perhaps somewhat ironically this included people from northern Europe, who were way too pale to look like Romans.) There's a bit of a tongue-in-cheek saying about ancient Romans: "They were not racists: They hated everybody equally."
8. And no, the Roman Republic was not significantly better than the later Roman Empire. The Republic/Empire distinction mainly concerned internal politics and government, not their expansionism. 

In other words, ancient Rome was everything that the modern far left is supposed to hate. Yet, some of them are trying to rewrite history, engage in good old historic revisionism, and claim that ancient Rome was this multicultural paradise where all nations and races were embraced as equals.

Why?

I have no idea. Probably because they hate white people, or something.