I really hate this take because it implicitly ignores the baseline murderous-ness of the systems and situations these leaders inherit. Nelson Mandela wasn't gonna rise to the top of the pile in 1920s Russia.
Furthermore, the people who underpin various states and societies (and the cultures and movements that shape them) do ultimately choose who rules them. Leaders only have freedom of action within the window of what their political capitol affords them. The people, or even just the ones that call the shots (this should be a familiar concept if you've ever seen a TV show centered around a medieval royal family) very much do set that window. Grant and Eisenhower's "failure" to thoroughly exploit conquered territory would have made them unsuitable for further leadership in antiquity for that matter yet they were both more or less instantly elevated by the existing power structure and elected to the highest office.
This is a bad take because it comes from linguistic ignorance. The "great" here doesn't mean the person is wonderful with a kind soul and a benevolent impact. It's not "great" as an extra intense "good".
It's great like a Great White Shark is great. Great like Great Britain is great. Large, impactful, encompassing. A person is said to be a "Great Person" if they are seen to have a disproportionately large impact on the course of history. It is this premise, of some individuals being able to have such disproportionate impacts (rather than everything being a product of the times) that certain philosophers and historians have objected to. It wasn't out of concern that we might be glorifying nasty people with the term; if that were it then we could simply change the terminology to "Impactful People" or something like that. Those who've lodged serious objections to the premise of great people would not be placated by this change in words.
Incidentally I remember my history teacher commenting that even if Marx didn't exist at that time, communism would still be born around that time in history.
Marx himself would say so. Key to Marxism is studying history to come up with a scientific theory which predicts the future course of society. If individuals can change the course of history through shear force of their will, bending society in unpredictable ways to suit their individual fancy, that throws a wrench into it.
But can anybody seriously say that if not for Napoleon, there surely would have been some other French general, inspired by Julius Caesar to conquer everything he could, who was simultaneously also a master tactician with enough skill to get as far as Napoleon did? I can buy the premise that somebody else in that political environment might have tried, but to get so far and embroil most of the world in war as Napoleon did wasn't a deterministic predictable consequence of the circumstance. You can probably predict a civil war, but not the Napoleonic Wars.
There's definitely problems with a 100% structuralist view of history too make no mistake. Things like politics, battles and wars are more prone to the effects of outliers and random chance just by their nature, you can't have 1000 people try to conquer Italy with one of the least loved chunks of the French Army at the same time, unlike how you can have 1000 people working on radio or flight at a time. On the other side of the coin without the French Revolution which he had no part in creating or driving he would have likely stayed a minor artillery officer or less in the Acien regime.