Sadly slavery has occured as far back as we can go. The Romans enslaved the Britons and most of the rest of Europe, Muslims captured and enslaved white sailors, the Egyptians enslaved the Jews, whites enslaved blacks, blacks enslaved other blacks etc, etc, etc. Depressingly slavery is well ingrained in human history and no country or race has not been involved in some way. No one should feel shame for what other people did hundreds of years ago. You can wish it hadn't happened and feel sorry for the people involved but no one alive today has any reason to feel personally ashamed for what happened.
What we may feel ashamed about is the slavery that still goes on today. Whether that's sex slaves being brought to Western countries from Africa or Eastern Europe, or Christian slaves in some areas of Islamic countries. It is happening now in front of our noses and is something we could be doing something about. If you want to feel ashamed about slavery feel ashamed about modern slavery.
