This is mostly about how Liberals get upset with celebrating deaths of people with even if they "totally disagree with them and agree they were bad" like Kissinger or Rumsfeld or whoever. Not saying that conservatives are celebrating Kissinger in particular.
Though a minority of conservatives hate Kissinger out of a broader sense of isolationism or just anti-Semitism.
It's a split thing. I was taught my antiwar principals by MTG type mincap Dad. He hated Kissinger for being the biggest dealer of death in modern history. I'd expect the crunchy/conspiracy conservatives to hate Kissinger.