Just to add some nuance here, Tan's comments weren't a death threat in the legal sense (or at least don't constitue a crime). It is perfectly legal (if inadvisable) to say something along the lines of "Politician X should die a slow painful death." It only becomes a crime if it is a highly specific threat. E.g. "I am going to shoot Politician X on Tuesday evening after they leave City Hall."

Just because it's legal doesn't mean it's not wrong.

I mean, he can legally say it for sure, and I wouldn't argue that the law should prevent him from that. But once said, everyone else has every right to condemn him for it.