The timing is suspicious.
Brexit was probably going to win. Until someone started a rumor about the crazy evil gunman shouting "Britain First" as he murdered the helplessly unarmed Marxist MP.
Americans were in open revolt about Federally-imposed multi-gender public school restrooms and locker room showers. Until someone shot 50 gay guys in a nightclub.
If there was a conspiracy to make the sheeple fearful and stampede them away from the surging alt-right movement, it would do exactly those type of things (which create salient examples of reactionary terror while making martyrs of dead leftists).
Remember the militia movement? I do. It ended as soon as the OKC Federal building blew up. And that's why we got a 2nd Clinton term.
There is more than a hint of pattern and practice to these public perception molding events.
For me it's started with the Reichstag burning in Germany. Same hubris of grander, planning, elitism... Anyway being suspicious of events is totally rational. Only if factually disproved can it be disregarded. However it may take too much time on an already limited individual lifespan.