Interestingly (well, to me at least), the Book of Leviticus promotes slavery - as long as it's enslavement of other peoples than your own. It comes a bit after where it tells us to kill people who eat prawns or have a hair cut. Ah, those merry, carefree days.
On another note, why not have a statue park in the midlands or where ever, with all the contentious statues put on display and notes about their 'crimes'* and the rest of their record? Largely, I suspect, because that would open up some terribly difficult questions about national 'heroes' which the population really wouldn't want to address.
I'm using ' ... ' as, of course, their crimes weren't crimes at the time.