"We don't need to feel shame or guilt about it, we didnt personally do it. But we do need to understand why it happened, and make sure the opinions, attitudes and institutions that enabled it to continue are not tolerated. We can't help the fact it happened, it is in the past."
This, acknowledge the horrors of the past and it and ensure it can never happen again and stamp out any racist attitudes that stemmed from it and are still present but we shouldn't feel anymore personal guilt for it than people born in Germany now should for the Holocaust. However we should acknowledge our past mistakes as a country more like Germany has, but that starts with education, not bashing people who acknowledge the horrors but literally can't do anything about it because we don't have time travel. And I don't feel any 'pride' for Britain have been on the winning side of either of the world wars either, I'm bloody glad we did because in both cases our side of the war was about defending from invasions by the other side who were occupying other countries and attempting to do the same to Britain, but relief is quite different to pride.
If we hold everyone on the planet responsible for the actions of their ancestors, then we are all scum.
This, not a single country failed to participate and profit from the slave trade in some way, from the African tribes who kidnapped and sold each other to the Far East and west who transported slaves across the world. And if it's not the crime of slavery its crimes against women, or gay people, or disabled people, or against some other ethnic minority. Every single country has a barbaric history, every single modern civilisation is born out of some war. Every single country still has some racism, whether it be against black people, or oriental Asians, or Indian Asians ect, all these need to be dealt with.