Statue Toppling is a Sounded Alarm, These 4 George Orwell Quotes Show Why

The moral standard with which historical figures like Edward Colston (and Jefferson, Washington, Columbus and others in the USA) have been judged by those who support the toppling of their statues is that involved among their various invested enterprises were slaves.
And there is outrage.

Today, the mineral Cobalt is mined in The Dem. Rep. of Congo by child slave labour (srcs: Guardian, Amnesty International), some proportion of which is almost certainly used in the electronic components of the device that you (likely) paid for and are currently using to read this. Likewise for the phones of every individual that video recorded and celebrated the toppling of Colston's statue.
And where is the outrage? 

So, somewhat like Colston in his day, you are a willing contributor to, and benefactor of, the financial eco system of present day slavery. It is not fair to judge you for this, though. The boundaries of the moral standards of the day are limited by what can reasonably be achieved whilst maintaining the practical care for those you care about the most. This defines the acceptable standards and social conventions of the day. This is true for today and for any other time in history. Some may find themselves in a position to do what may possibly maximize well being for their community, civilization and humanity. I certainly encourage these endeavours; it seems a contradiction to focus attention on long dead contributors to heinous practices whilst ignoring the same practices occurring right now.

However, it would be unjust for someone in the future to think they live in a time of moral purity, then look back and judge you as entirely immoral because of your contribution to the child slavery used to enable your smart phone. Equivalently, it is unjust to judge figures of history on the false presumption that you live in a time of such moral purity. There is no utopia, there never was and there never can be. Statue toppling is an outcome of outraged minds driven by blinkered moral grandstanding of an high order. This is Puritanism fused with identity politics. It is ideologically equivalent to book burning.

How and why a totalitarian ideology seeks to controls everyone's mind.
Explained by 'O'Brien', the totalitarian idealogue from '1984' by George Orwell.

Warts and all, British history is displayed publicly across the country. It outlines a part of our cultural heritage and remains there as an opportunity to understand ourselves not in terms of good guys and bad guys (there is no such thing), but as everything in between. We have more monuments and statues openly on display than most other civilisations. The nation is effectively an open air museum. To cede control of our history to ideology is a form of censorship and a submission to ideologues who desire power over our thoughts. No person alive or historical is a pure untainted character. If you appoint yourself as judge. the rule is set that anyone can judge; you will then be judged soon enough. This is the purity spiral, and it is a long way down.

 Orwell tells us where this ends, if the idealogues that support statue toppling are not sufficiently opposed.

Statue toppling and removal of monuments at the behest of political activism may yet seem a distant world to that of Orwell's 1984. Nonetheless, the parallel signifies that a trip wire has been triggered and an alarm sounded. This is one of many such trip wire alarms that Orwell left for us to demonstrate that it is authoritarian ideology and the machinations of totalitarianism that drives such alarm triggering events.

Intersectionality, or 'wokeism', is an identitarian ideology that has motivated those that have been captured by it to approve of the defacing of cultural heritage monuments like Winston Churchill, Abraham Lincoln, and the attempted fire setting of the UK flag on the cenotaph. This could be seen as an attack, even interpreted as a larger threat. Rival identitarian ideologies will almost certainly emerge re-actively. 'Either/or' will be the false dichotomy presented. Both 'sides' can be rejected. Rather than the unthinking rage and passion of cult-ish ideology, liberal democracy based on Enlightenment values and the principles of reason - a subset of which I have elsewhere called 'anti-prejudice absolutism' -  presents another proposal.