Once again, you must take them in context. I can easily envision a political operative like Rove or Carville say when refuring to an election, “We have to kill him and drive a stake through his heart so he can’t rise from the dead like Carter”. Taken out of the electoral context, it seems a clear death threat when political “death” was all that was contemplated. They wanted such a crushing defeat that no political resurrection would be possible.
The UK tourist was plainly tweeting about partying using today’s slang. What about a Man U soccer player saying they will destroy America before a friendly match? Context.