After President John F. Kennedy was murdered, Mrs. Kennedy's pink suit was stained and soiled by blood and brain matter: on the plane from Dallas back to Washington a fresh, clean outfit was offered -- "better change before we land...all the cameras will be on us..." -- and Jackie answered, "No. Let them see what they've done."
Everything you read about the Kennedys has that story in it, and probably the various movies, too....
In the Pablo Larraín 2016 film Jackie, she says, in a focused, injured, ticked-off whisper, "There were 'wanted' posters everywhere with Jack's face on them! Let them see what they've done!"
What she seems to be saying, there, is -- well, this film version is making 2 points:
1. In politics, people's desire to win and frustration if they lose can become too emotional and extreme, and putting up posters saying the president of the U.S. is "wanted" like a criminal or whatever, could possibly provoke mentally unbalanced people to perpetrate violence.
And 2. In politics -- and in other situations, too -- better to keep it light, don't rile up the crazy....
"Don't rile up the crazy" is excellent policy, in my opinion.
However, I question the idea that the "wanted" posters drove Lee Harvey Oswald (or whoever) to murder President Kennedy. Stuff like that -- wanted posters, or enactments of pretend-exaggerated-aggression against the current president, or any elected official, are dumb, unhelpful, and in bad taste. But I don't think such an exercise in bad taste inspires people to suddenly want to commit murder.
Whoever planned the 1963 JFK hit was organized, had it planned out, motivated by extremism or evil or profit...and probably paid no attention to posters plastered by crackpots.
It would be different if elected officials made a "joke" or "exaggeration" like that -- it would seem then like sort of "an order," or "encouragement," if a troubled person chose to take it that way.
But any common schmuck can put up posters saying a politician is "wanted." It doesn't carry the same weight as it would if someone in Congress or the White House said it. I mean, do we obey commands or act upon suggestions from, for example, graffiti written on bathroom walls? Probably not.
But a person can see how the widow would be freaked out on several levels by several things, at the time, & the silly "wanted" posters didn't help.
I've read that on the morning of Nov. 22, 1963, the president showed Jackie a newspaper advertisement purchased by someone who imagined that they didn't like him -- a black border all around a photo of JFK and some kind of negative mean ominous message printed on.
"We're heading into nut country," he said lightly.
I think the scene in the 2016 movie was combining that newspaper-ad-vignette into the "Let them see what they've done" verbal exchange.