We did have the Nuremberg trials to prosecute Nazis after their empire collapsed. The ICC is a formalization of that principle on more solid legal footing
Obviously its power is limited when it comes to prosecuting people currently in power or people that have favorable standing with their current host country. It can only make the live of those people a little less pleasant by issuing arrest warrants that limit their ability to travel internationally. But governments do fall from time to time, and when that happens the ICC provides a solid mechanism for prosecuting them for war crimes and crimes against humanity, in a way that is fair and has rules that were solidly established before the crime was committed
Too bad that such trials are often evidence based.
And in a certain sea-side part of a certain country, there's active bulldozing and paving over hard white leftovers of evidence of the misshaps that could later be prosecuted if they weren't so effectively crushed and hidden.
Obviously its power is limited when it comes to prosecuting people currently in power or people that have favorable standing with their current host country. It can only make the live of those people a little less pleasant by issuing arrest warrants that limit their ability to travel internationally. But governments do fall from time to time, and when that happens the ICC provides a solid mechanism for prosecuting them for war crimes and crimes against humanity, in a way that is fair and has rules that were solidly established before the crime was committed