If you find this horrifying (and I hope you do, because there can be no moral justification for celebrating murder), then I encourage you to really think about whether we would not be better off without such extremist language poisoning people's minds. We have to try to stop escalating, or the cycle is going to destroy our society.
If someone or something is a threat to democracy and rule of law, then they are. Period. I think pretending the ruling political party in the US is not intentionally destroying the government is not a valid strategy.
This is not an endorsement of what happened today. I worry this will have a big chilling effect on political speech in the country.