I despise David Duke. I despise that Trump has helped bring Duke and the rest of the neo-Nazi, white supremacist right into the mainstream. But he doesn't "deserve a bullet." People - certainly people of prominence in a public setting - should never speak like this. Going from being a Klan/Alt-Right fellow traveller to inciting murder is not necessarily progress. In fact, I'd say they stem from the same violent, authoritarian mentality that inhabits the whole Trump family. It's of a piece with so many Trump supporters and surrogates calling for Hillary Clinton's murder or 'execution'.
What any us of 'deserve' - who knows? We don't kill people. We don't kill people we don't like. Even evil people.
These are awful people.