As you've said, Racism is not the same with Slavery, because slavery or slave trade in itself is driven by the need for conquest. Great Britain colonized a lot of places in Africa, and they didn't do it out of racism. It was just a more developed country in another content, exploring into other places. Also racism and it's effect can be honestly devastating. I've been discriminated for being black and even more, for not being financially bouyant. Some people are openly racist, others are... Secretly racist. I think it's a concept what will always exist and will probably not change anytime soon.
Great write-up