Arguably the loveliest spot in Sydney is Mrs Macquarie’s Chair. The city’s surviving sandstone grandeur owes much to the legacy of her husband Lachlan Macquarie, governor of NSW from 1810 to 1821. Macquarie Street, Macquarie University and Macquarie Bank, among many landmarks and institutions, mark his memory as a giant of Australia’s colonial period.

He was also a bit inclined towards genocide. In 1816, Macquarie declared a covert war against the remaining Aboriginal tribes around Sydney. His written instruction to the commander of the 46th Regiment (slightly edited) was explicit:

“On any occasion of seeing or falling in with the Natives, they are to be called on to surrender themselves to you as Prisoners of War. If they refuse to do so, make the least show of resistance, or attempt to run away from you, you will fire upon and compel them to surrender. Such Natives as happen to be killed on such occasions are to be hanged up on trees in conspicuous situations, to strike the Survivors with the greater terror.”

The consequent slaughter continued for most of 1816. These days, we’d call Macquarie’s orders an official mandate for ethnic cleansing, a crime against humanity. In 1816, it would have been considered a form of housekeeping, albeit one you wouldn’t necessarily advertise.

My point, of course, is that history discloses at least two Lachlan Macquaries. Can we, in these modern days of what some label political correctness and others call not celebrating evil continue comfortably to commemorate a man for the good he did, or at least the influence he had, while ignoring the appalling underside?

Melbourne University has just made one such call, coming down on the side of revision. The Richard Berry Building, which houses the university’s department of mathematics, will shortly be renamed, as Crikey reported in January. Professor Berry was by any measure an eminent man: a fellow of the Royal College of Surgeons, chair of anatomy and later dean of the Melbourne medical school, teaching there from 1906 to 1929. Apparently he revolutionised the teaching of anatomy. He was honoured in 1959 with the title of professor emeritus (academia-speak for “legend”).

The Australian Dictionary of Biography euphemistically describes the good professor’s fascination with “the Australian and Tasmanian Aboriginals and the metrical and non-metrical features of their skulls”. Translation: Berry was a leader in the then-trendy field of eugenics, the pseudo-science of measuring intelligence and other qualities by reference to genetic differences, especially race. In short, he spent much of his career trying to prove that Aborigines were relatively stupid. He also advocated sterilising 25% of the population to breed out mental deficiency.

If Berry had lived a decade later in Nazi Germany, the only thing named after him would be some Nuremberg transcripts. As it was, he got almost a century of respect before the tide of history finally caught up last week.

The trend of name-changing is growing, and there is no shortage of available targets. Yale University is changing the name of Calhoun College, because US Vice President John C. Calhoun (1825-1832) was a leading opponent of the abolition of slavery. That sounds bad, because it is, but come on, the guy was from South Carolina.

Cecil Rhodes, the father of British colonisation of southern Africa and founder of the De Beers diamond conglomerate, has become a lightning rod for the paradox of historical memory. He was a massive racist: “I contend that we [Anglo-Saxons] are the first race in the world, and that the more of the world we inhabit the better it is for the human race.” Still, in the 1800s, this was hardly a controversial view. And there’s no question, for better or worse, that Rhodes changed the face of a large part of the world.

It’s all terribly difficult. In Russia, there’s a counter-revolution of historical re-revisionism going on, as Stalin’s memory is progressively re-burnished. Sure, he killed tens of millions of his own people, but in that country’s present political environment it’s unsurprising that the other side of the same coin — the historical fact that he defeated Hitler and expanded the Russian empire — is being celebrated once more.

The US has some tricky problems. Most of the early presidents and founding fathers were slave-owners; Thomas Jefferson’s god status masks some grubby realities, including maintaining a secret second family with a slave mistress. Even Abe Lincoln, the Great Emancipator, did think slavery was bad but was equally sure that African-Americans were not the equal of whites and that the two should never mix. There’s a fair case to be made on the complete historical record for dynamiting each of the presidential faces off Mount Rushmore.

When the Russians finally entered Adolf Hitler’s bunker in Berlin in 1945, they found his corpse in the garden. Thinking ahead to the undesirability of giving posterity a grave site, they obliterated Hitler’s remains and buried any record that they’d done so. You can see their point.

True, Hitler lost, but so did Napoleon, another megalomaniac and murderer of millions, who rests peacefully in his grand tomb at Les Invalides. So that’s probably not the real point of distinction.

There really isn’t a way of drawing a clear line on this. Mostly, those who shriek “political correctness gone mad!” every time there’s a push to change a building name or pull down a statue are just being hypocrites. Nobody complained when Saddam International Airport got a name change, but from (say) Pauline Hanson’s perspective, wasn’t he not just a megalomaniac but also a strong leader who kept his country out of civil war?

On the other side of the debate, the quicksand is equally treacherous. If Aung San Suu Kyi doesn’t lift her game on the genocidal persecution of Rohingya still happening in Myanmar under her watch, will future guardians of historical purity be forced to protest against her name being put on things? Including, for that matter, the Nobel Peace Prize she already possesses.

There will be many Barack Obama Places, buildings, submarines and institutions dedicated to global harmony to come; but Obama maintained unlawful indefinite detention at Guantanamo Bay and vastly increased the scale of extra-judicial assassinations (by drone or SEALS) carried out by US forces in sovereign nations which did not give their consent. Those, not to be too cute about it, are war crimes.

When the sides of an argument are framed by hypocrisy no matter which way you look, you’re in the wrong room. The correct answer to the question of whether Macquarie Street should be renamed is that there is no correct answer. Not one I can think of, anyway.

Profoundly unsatisfying as that may feel, it’s not actually that bad a thing for a mature society to learn how to live with a degree of contradiction in how it reflects its history. It’d make a change from shouting logical inconsistencies at each other.