If the truck was hijacked, then I wouldn't be surprised if this turns out to be a spur of the moment thing due to our stupid actions last night.
Because everything in Europe was totally chill before that, and Sweden = literally Donald Trump despite not even being a NATO member?
It seems pretty spur of the moment to me. He'd have done it sooner or later, yes. But there is a reason why they are and have been killing us for years, and it is a hell of a lot more complicated than a few controversial passages of the Koran. They view us as occupiers. What we did last night did nothing to stabilize Syria and everything to only further inflame anti-American sentiment.
I mean, whatever your opinion on the military action this seems wrong. I don't see why Salafis would be particularly irritated at a strike aimed entirely at the leadership of the Syrian regime.