They're not even smart, they're asking for war on all fronts, they're attacking Jews and Christians in the US, Russia, all over Europe, they're beheading Christians in Indonesia, they've killed millions of Christians and animists in Africa, they're taking on the Hindus in India. It's like they're asking for the whole world to move in and wipe them out.
The customs of warfare of the 6th and 7th centuries AD, in a part of the world where brigandage and politics were indistinguishable, where slavery had existed forever and no one dreamed of it ending, where cities taken in seiges were routinely sacked, adult men all killed, the women and children sold into slavery, where the main booty taken in raids was human captives, livestock second, moveable property a distant third, where "idolatry" meant public worship of what you and I would term demons, sometimes by human sacrifice.
A literalist can find no standard to appeal to against the practices of the time his scriptures were written. If he is being literalist about the Sermon on the Mount and the Golden Rule, about a light in that darkness trying to move men to greater humanity toward one another, that is one thing. If it is being literalist about the standards and maxims of a successful warrior chieftan who personally commanded at a dozen battles, conquered much of Arabia, distributed booty, ordered the execution of inhabitants of cities that resisted his army, etc, then that is something else. If it is even being literalist about the Old Testament uncorrected by either "Midrash" or the New, you would see much of the same.
Islam can be civilized only where some authority to interpret the meaning of their scriptures is acknowledged, something set over the literal text. Whether that something is extracting the principles from traditions by analogic reasoning, gradual reform by a sort of common law equity, guidance by the consensus of the community, positive legislation by more enlightened, later citizens, decrees by enlightened monarchs, or some revered teaching authority, moral progress is possible only where their is some right of legislation by later men.
Why is such a power of legislation resisted by some extremist partisans of traditional religions? Simple enough. They see in all later progress a luke warm falling away from the supposed purity of what they take as their revealed law. They see falliable men appointing themselves to a role they imagine was restricted to their founding prophet or to God. They see flat disobediance to what they think of as prior law.
They have no other real standard to appeal to. The promptings of their reason or their conscience they take as temptations to arrogant disobediance, not as morality. They put their old book with all the trappings of its gory historical setting above first the law, and second their own thoughts.
Within Islam, the tradition of excessive literalism like this, justifying or even enjoining barbaric practices because such things were done among brigands of the 6th and 7th centuries, has its own history and arose for its own reasons. Many present partisans of that view trace it to one al-Wahhab, an 18th century literalist "theologian". Who in turn was attempting to revive and intensify the views of one Ibn Taymia, a medieval jurist and theologian marked for his bigotry and iconoclasm. Ibn Taymia in turn appealed to the prior example of a jurist named Hanbal from much earlier, who upheld a sort of naive literalism as a form of populist resistence to innovations by rational theologians associated with the rulers of his day.
It is a story of the radicals going to further and further extremes, initially for somewhat comprehensible motives at a time when the distance in time and in practices of their standard vs. the world around them was not so great. The principle the early ones set up becomes more unreasonable in later practioners. They do not react to this by softening the edges of the doctrine, but by greater fury at the world for deviating from their standard of judgement. Down to today, where the craziness of the view is palpable to anyone not steeped in the same extremist sub-culture.
When Hanbal set up the standard of literalism, he was being persecuted by court theologians for not agreeing to their abstruse innovations about free will or the problem of evil or predestination or the incorporeality of God. He refused to argue with them on their own terms, just quoting the text back and them and for the rest remaining silent. He was not aggressive, but defensive, in his appeal to literalism. He wanted simple people who took their scripture literally to remain unpersecuted for the naive simplicity of their beliefs. Religious populists loved him and hated his persecuters as elitist innovators and heretics.
Centuries on, when Ibn Taymia appealed again to Hanbal's literalism, an enourmous variety of theological dispute, philosophic positions, political history and factionalism, diverse popular superstitions, mystic teachings by this holy man and that, had passed in review. The Islamic world had experimented with scores of positions. It was also disunited and at war, internally and externally, from end to end. Ibn Taymia violently condemned essentially the whole of that varied history as the cause of the present disunity, and sought to restore unity through literalism. But now not a defensive or naive one, but an aggressive and counterattacking one. One that would condemn and fight against all variations within Islam as imported forms of unbelief, corruptions of the original intent of the prophet. It was an opposition position in his own day; the man died in prison for his intransigent defiance of the rulers. It grew afterward.
Al-Wahhab in the 18th century studied Ibn Taymia and followed his program. He accepted Ibn Taymia's diagnosis of the supposed cause of the obvious decline of Islamic civilization. Not being faithful enough to the original teaching of the Koran and to the practices of the 7th century, the power that drove their original unity and conquest of so much of the world had evaporated into stagnation, and the worldly cynicism of the Turkish court at Istanbul. The way to revive the power of Islam was supposedly to bring back Arab rule against the Turks, and aggressive literalism against the "go along" opportunist interpretation of the traditional clergy, who were seen as 'tyrant's baggage and lickspittles' (to borrow a phrase from another context).
There are traditional schools of Islamic theology that go quite the other way, that allow of interpretation and of moral progress. The theological fight within the Islamic world for the last century has been between legal and rational theology traditions that had adapted over the years, and who revere men like the medieval theologian al-Ghazzali, against literalists of the tradition of Ibn Taymia (including, but not limited to, the disciples of al-Wahhab).
If men who are literalists about the habits and practices of a successful 7th century brigand win that fight, then you can expect to see the barbarisms of the 7th century replayed in the 21st - but with 21st century weaponry. That is what we are fighting against, trying to keep men with that opinion away from serious political power in the Muslim world, and away from access to modern weapons.
I hope this helps.