Serbia should have been allowed to genocide more Muslim Bosnians and Albanians.

The NATO intervention killed and displaced more civilians than the Bosnian genocide.

The Serbian president Slobodan Milosevic had shown his ruthlessness earlier in Bosnia, and now, facing armed attack from Kosovo nationalists, attacked Kosovo, killing perhaps 2,000 people and causing several hundred thousand to become refugees.

An international gathering in Rambouillet, France, was supposed to try to solve the problem diplomatically. But it presented terms to Yugoslavia that seemed certain to be rejected: NATO control of all of Kosovo, and NATO military occupation of the rest of Yugoslavia. On March 23, 1999, the Serbian National Assembly responded with a counterproposal, rejecting NATO occupation and calling for negotiations leading “toward the reaching of a political agreement on a wide-ranging autonomy for Kosovo. . . . ” The Serbian proposal was ignored, and was not reported in the major newspapers of the United States

The following day, NATO forces (meaning mostly U.S. forces) began the bombing of Yugoslavia. Presumably, the bombing was to stop the “ethnic cleansing” of Kosovo, that is, the forcing of Albanians out of the province by death or intimidation. But after two weeks of bombing, the New York Times reported (April 5, 1999) that “more than 350,000 have left Kosovo since March 24.” Two months later, with the bombing still going on, the figure had risen to over 800,000. The bombing of Yugoslavia, including the capital city of Belgrade, apparently intended to unseat Milosevic, led to an untold number of civilian casualties.

From the People's History of the United States, Chapter 24

Also Ghadaffi should have been allowed to butcher his population.

Again, the French airforce and subsequent NATO occupation has killed an order of magnitude more in the last decade than Ghadaffi managed in his entire time in office.