In fact, the vast majority of those ancient Roman statues are now housed in museums and galleries in Italy. If you look into the "slave culture" of ancient Rome I think you'll find that it wasn't at all the same thing as was practised in the US. And there aren't too many descendants of ancient Rome left to take offence. There may be a debate to be had about when modern history, of the kind that all too sharply informs our attitudes to modern-day events, morphs into ancient history. The cutoff, if there is such a thing, may be at different points in different cultures. There may also be a debate to be had regarding those ancient sculptures about whether they should remain as examples of great art. You tell me at which point, for example, nude art is no longer good enough to not be pornography. There's no black and white, but there is a red line beyond which political partiality imposed on others can cause perfectly unjustifiable offence. And we do live in democracies in which we accept that personal freedoms may be compromised at the point where they start to tread on other people's toes. It's also well worth remembering, when you consider those confederate statues, that slavery is by no means dead in today's world.