Do they? Can they really not just say "Obviously a whack job" and leave it at that? Still, I come from a country where the only Prime Minister to die in office did so while having a swim at the beach so we tend to be a bit more relaxed about things. I believe I've told the story of the time that the Prime Minister was (unexpectedly) walking past and my brother and I were having an idle (and entirely joking) chat about running over and poking him in the eye and discussing the difficulties that his glasses would pose and wondering if that's why he wore glasses - to avoid eye-pokes. We looked up and realised that a very senior police officer was well within ear-shot of us and indeed holding back giggles, whether at our conversation or amusing double take I will never know.
But we have had 4 sitting Presidents assassinated (Lincoln, Garfield, McKinley, Kennedy), 1 sitting President injured (Reagan), 1 former President injured (Teddy Roosevelt. while campaigning as a 3rd party candidate for President), and at least 14 attempted assassinations that did not result in serious injury. Of the last 10 US Presidents only LBJ did not have someone try to kill him in office.
Kennedy - Killed, also a man named Richard Paul Pavlick planned to car bomb him
Nixon One person smuggled a gun into an event, another was going to crash a plane into the White House
Ford (who by the way is the only person so far to be President w/out being elected as President or VP - was appointed to VP after Agnew resigned became President after Nixon Resigned) Lynett Fromme (of Manson Family) and Sara Jane More both tried to kill him
Carter - Raymond Lee Harvey mentally ill claimed to be part of a 4 man team.
Ronald Reagan Shot by John Hinckley Jr.
George H. W. Bush - attempted bombing Kuwait University
Bill Clinton - Frank Eugene Corder Tried to hit the White House with a single engine Cessna, Francisco Martin Duran fired 28 shots at the White House. Attempted bombing at APEC Forum in 1996,
George W Bush Robert Picket shot at the White House. Tbilisi, Georgia Vladimir Arutyunia threw a live grenade towards the President during a speech,
Obama - Oscar Ortega-Hernandez shot 7 times at the White House cracking a window.