Back in 2004, in one of his most recognized messages to America, Osama bin Laden, responding to then President George Bush Jr.'s claims that Al Qaeda hates freedom, rhetorically asked, "If so [if Al Qaeda hates freedom], let him [Bush] explain to us why we have not attacked Sweden, for example."
Days ago, on December 11, an Al Qaeda affiliated suicide bomber attacked Sweden—the first terrorist attack in Sweden in three decades, and its first ever suicide attack. The attempt largely failed (only the bomber died, two Swedes were injured). Even so, it "could have been truly catastrophic," said one official.
So much for Sweden epitomizing Al Qaeda's "respect" for freedom. Why the change in policy? In fact, according to an audio-recording issued by the terrorists minutes before the attack, the vitriol is such that "all Mujahadeen [jihadists] in Europe and Sweden" are to prepare for action: "Now is the time to strike, don't wait any longer."
Would-be future jihadists were further advised to attack with "whatever you have, even if it is a knife"—a bag of nails was found near the body of the suicide bomber—indicating that the jihadists may have been taking lessons from Al Qaeda's popular online magazine, Inspire, which, among other things, offers creative tips on how to transform household items into lethal weapons.
As for motives, according to the audio-recording, there are three: Sweden will be a target of the jihad "as long as you do not  end your war against Islam and  humiliation of the Prophet and  your stupid support for the pig Vilks."
The first point—"war against Islam"—appears to be a reference to Sweden's 500 troop presence in Afghanistan. Yet Sweden is only one of nearly fifty countries—including Muslim ones—to have a presence in Afghanistan; Turkey alone has contributed nearly four times as many troops. And most of these nations have not (yet) been targeted. Moreover, Sweden has been a troop contributing nation since July 24, 2003—well over a year before Osama portrayed it as a neutral country, undeserving of attack. (Perhaps he meant Switzerland, which is known for its neutrality, and is often conflated with Sweden by Middle Easterners?)
The second and third reasons cited—"humiliation of the Prophet" and "support for Vilks"—are one and the same and, in fact, the immediate reason behind the attack. Context: back in 2007, Swedish artist Lars Vilks drew unflattering caricatures of the Muslim prophet Muhammad. Since then, Al Qaeda has set a bounty on him (the reward increases if he is "slaughtered like a lamb"); he has already been physically assaulted and his house nearly burned down.
Swedish freedom of speech and expression, then, is what prompted the attack. In fact, eliminating Western freedoms—or at least conforming them to the dictates of sharia law, which, among other things, forbid mockery of Muhammad—is a longstanding Islamist goal. Nor is it limited to violence; rather, the West's very legal system is being exploited, through Islamist "lawfare" designed to censor free speech concerning Islam (prompting countermeasures such as the Middle East Forum's Legal Project).
More generally speaking, when assessing why jihadists attack this or that country, there are other factors to consider, such as capability and timing ("Now is the time to strike, don't wait any longer," said the recording). The fact is, from an Islamist point of view, Sweden has long been deserving of attack, simply for contributing the 500 troops to Afghanistan—just as the nearly fifty contributing nations are all fair game.
More to the point, even the most neutral country that has no dealings with Islam is a potential target; if and when it gets attacked is based on if and when the Islamic world resurrects the caliphate—again, capability and timing being the ultimate determinants. Once a militarily capable caliphate is established, offensive jihad to subject the world to Islamic dominion becomes no less obligatory than stifling mockery of Muhammad. In short, it is not about what this or that country does; Islamist animosity for infidels is intrinsic, kept at bay only by circumstance.
And so, to respond to Osama bin Laden's 2004 question "why we [Al Qaeda] have not attacked Sweden," the answer is—because the time was not quite right then.