Because that was a thing that a candidate for the President of the United States suggested. Out loud. In public. In front of thousands of people.
Here was Hillary’s response because, honestly, what other response could she have had?
"A person seeking to be the President of the United States should not suggest violence in any way." pic.twitter.com/Uu55CBCqdK— Hillary Clinton (@HillaryClinton) August 9, 2016
On the plus side, he’s like Joffrey or Ramsay Bolton. The more vile he is, the more satisfying it will be when he loses.