I live fairly near Bristol and, like many major cities, its built on the back of things we now see (well, some of us) as utterly abhorrent. Just like Glasgow, Manchester, parts of Birmingham, and certainly London. There has been debate about Bristol's approach to Colston for at least a decade, as it doesn't fit well with the city's overall relatively inclusive, progressive stance on most things.
I don't think a revisionist approach to history is the answer, though. I agree with the pp who said that sticking such things in a museum or somewhere with an explanation might be an option or melting the dratted things down and having something more appropriate or inclusive in their place. I'd also be in favour of a small plaque on the original site if those decisions were taken.
Attitudes change all the time, but sometimes it's a very slow process. I do a little editorial work, and while it's not my area of expertise, some of the other editors are very clear about the fact historical texts and memoirs in particular can prove tricky. The best approach I've seen recently was a paragraph at the start of the work that said something along the lines of "This work is a product of its time. Contemporary readers may find some of the attitudes and approaches portrayed incompatible with present-day approaches".
I'm also fairly sure that the future will judge us and many of our attitudes very harshly. Things that are now taken for granted, like animal cruelty when it comes to much of the food chain, our wilful blindness to environmental change, and our pursuit of materialism at all cost, and our willingness to look the other way in the light of modern slavery (still, as long as those crops get picked and those cars get washed, those accessory babies get nannied to sleep and so on, eh) are likely to feature fairly high up the list of "What the *ing he** were they thinking? WERE they even thinking?"
Still, history's written by the winners....
(And no, I'm not implying everyone with a nanny has "accessory children", I've known those where their jobs or personal circumstances meant they had to have a nanny and the children were very much wanted. I've also encountered people who seem to see their kids as the walking, talking equivalent of a designer handbag they can pose with for publicity purposes.)