Edit: Guess who won't face any accountability.
First of all no one did this on national TV. Perhaps you referring to edge lords on the Internet making snide or rude comments. This is nothing to worry about. I heard people talk about hanging or shooting Obama for several years when I lived in Idaho. Celebrating and fantasizing about killing the President did absolutely nothing.
Second, we already live in a society where the right wing is constantly calling for violence. They have been openly talking about killing people from the Democratic party for decades. Rush Limbaugh was particularly found of this and he received the Medal of Freedom.
Let's be clear here, a couple of edgy people have celebrated his death. A lot of people recognize he was a piece of shit and are not upset at all other than to say no one should have to die this way.
The violent rhetoric comes regularly from the conservatives. Even the president of the United States sent a message he was bringing the Department of War to Chicago to enact an apocalypse. Kind of blows a few edge lords cheering on Kirk's death out of the motherfucking water.