Should one kill Hitler?
Imagine at some point in the future we're able to travel back in time. Should one kill (baby) Hitler?
On the one hand, it could save tens of millions of lives in Europe, prevent the Holocaust as well as the destruction of entire European cities.
On the other, without World War II, Stalin might have felt emboldened to conquer Europe. Or a more able revanchist could have seized power in Germany and prevailed, whereas Hitler - refusing the advice of his generals - undermined his own military successes.
America could have remained isolationist, or at least not intervened in Europe. There wouldn't have been a postwar liberal world order, with security in (Western) Europe, free trade, prosperity, and without great-power war. Decolonization would probably have been slower. All of East Asia could be under Japanese rule. Fascism, eugenics and antisemitism would not have been as thoroughly discredited as they were. The State of Israel would not exist.
I would err on the side of caution. Better to stick with the devil we know than gamble on an uncertain outcome.
Would you take the chance?