People aren't mad because a few libtards are doing a little gravedancing in isolation. So what, really? People usually gloat when political opposition dies. If a piano fell on Stephen Colbert, I'd chuckle. People are mad because the mainstream left, going all the way up to the former Speaker of the House and Presidential Candidate, has been openly calling for and celebrating vigilante violence as a political tactic for about 10 years now, ever since gangs of thugs assaulted people attending Trump rallies during the 2016 campaign, if not before then. The message has been clear for years now, "Republicans are Nazis," "It's okay to punch Nazis," "Our grandfathers landed at Normandy to kill Nazis, not debate with them," "an antifa assault is just like D-Day, really." They're not just gravedancing because lol, opponent gone. They're celebrating because this is how they want politics in America to work. If you're on the right, they want a vigilante directly inspired by their calls to violence to come kill you. They want you to be scared of being openly conservative, scared you might die. They want to go on TV, call for you to be killed with the not-so-subtle, "He's a Nazi, and we used to kill Nazis," and then celebrate when somebody kills you to let everyone know that's what they want and that it's perfectly fine.
Charlie Kirk's assassination is the next escalation in a decade of officially sanctioned and celebrated leftist violence, and if something isn't done now, there will be a lot more of this.