The people who push the "Rome was multicultural" are abusing the ambiquity of the term itself. As an empire, Rome obviously had multiple cultures, and thus was multicultural in a sense. But that is not how the term is used usually. Multiculturalism is used to mean that your culture should not matter in how you are treated in the state. This obviously was not how Rome worked.
The Latin culture was the norm, and if you failed to adhere to that,
or the Greek culture,
you were considered inferior.
doesn't mean that the Romans treated subjugated peoples as equals, which the modern usage of multiculturalism implies.
There's this cool concept called "slavery" where you move people from one place to another against their will. Rome had a habit of enslaving prisoners of war and shipping them home where eventually they'd become free men and their decendants maybe even citizens because multi-generational slavery is a more modern concept linked to chattel slavery. So a victory in Thrace results in an influx of Thracians in the Empire, a rebellion in Germania brings in Germans and fighting in Arabia Felix distributes
"slavery" where you move people from one place to another against their will. Rome had a habit of enslaving prisoners of war and shipping them home where eventually they'd become free men and their decendants maybe even citizens
