Without specifying a time period and or place you are asking about a time period spanning somewhere between 1,000 to 2,000 years depending on how you define “Rome” (fall of the western empire in late 400s AD or Constantinople in 1453 or many other arbitrary dates people have chosen) in addition to spanning three continents. In that incredibly vast expanse you will find examples of comparatively very fair and just rule to outright genocide and enslavement. There was no one size fits all approach to rule and it would vary greatly in the millennium or two it existed not only from place to place but changing in one place overtime. Really no way to properly answer this question. They could be quite harsh on rebels, criminals or enemies but not particularly more so than contemporaries or pretty much any other empire that preceded or followed them. So you will be able to find plenty of examples of “vicious Roman rule” but it’s certainly not unique to them or a blanket policy that covered its massive territory for an incredibly long time. I’ve always thought that particular line (great song) was partially inspired by the fact the Romans crucified Jesus given the preceding catholic verse and just works particularly well. But again pretty much any empire could be perceived as vicious rule to our modern sensibilities. But Achaemenid or Macedonian rule don’t flow quite as well lyrically.