Sher this is a historically relative point. Slavery has existed in many cultures for thousands of years. Europeans brought over 12 million slaves to the americas --as a an aside it shouldn't be called the european colonisation, rather the african forced colonisation as only about 2-3 million european colonists arrived in the same time period--, this is an appalling number and represents an industrialisation of the heinous act. However, what percentage of the world's population was that? Vs.. say entire cultures such as India's caste system which perpetrated a segregated system since the Aryans destroyed the Harrapa/INdus valley cvilisation? How many people were there on the planet then? What percentage of slavery existed in the 2nd cent BCE vs. say the 1700s?

To suggest western racism has been more genocidal is a ridiculous rewrite of history. Ask the polynesian tribes conquered by the Maori or the various civilisations/states oblidterated and subumed by the Han chinese or Mongols!