that's just not true. Bristol was the 2nd city in the UK way before the slave trade started. Both Liverpool and Bristol had merchants who were involved in the slave trade, but to suggest it was only the slave trade that allowed both cities to prosper is a little wide of the mark.
people aren't saying it was long ago, people are saying the institution of slavery was not built upon racism. when the first settlors arrived in Jamestown and Roanoke, you can guarantee they had never seen anything other than a white face. The fact the first settlors did not enslave the local population tells us racism and slavery was not in their thinking. Slavery came later, and it was the institution of slavery in the south that fostered the racism we see in the US today. We had no such institution in the UK, and whilst I'm not going to say racism does not exist in the UK, racism here is borne out of something completely different than in the US. The UK had its empire, which led many to believe that coming from the metropole somehow made you superior. This has affected all empires throughout history so its not unique to the UK
I don't disagree. However you can see that the narrative is often hijacked by those who wish to push an agenda whereby we must have this collective guilt for something that happened in Africa and the US and was caused by African tribal leaders enslaving their own and selling them to Europeans who were all too willing to transport them to the New World. Why aren't modern day Africans being held to account in the same way when they are equally as culpable?