How famous does someone have to be joke about a politician dying before it’s a problem? Tan is less famous than Charlie Sheen or Johnny Depp, who have joked about Trump dying.
Also, from Wikipedia: “Tan supported the 2022 recall campaign against progressive San Francisco District Attorney Chesa Boudin. Tan donated at least $100,000 to the effort. Tan blamed Boudin for physical attacks on Asians.”
There’s a fair argument that Tan is joking about violence against people whose policies are facilitating actual violence.
However, after acknowledging that Tan shouldn't have done this, it doesn't look serious. Drunken rants on Twitter are not important in and of themselves.