Middle Eastern politics tends to be utterly cynical, so that wouldn't surprise me.
As for the passages you refer to, it's true that they can't be changed. But they are open to different interpretations.
Mainstream Islamic teaching, for example, maintains that in the earliest sources from which Islamic teachings are derived, the Qur’an and stories about the sunna, the records of the example set by Prophet Muhammad, jihad is connected with another Arabic word, sabr, which is associated with patiently and non-violently resisting wrongdoing. In the early years of Islam, this is how Muhammad and the first Muslims dealt with the harsh treatment they received from members of their own tribe. They didn’t respond with violence. They just put up with it.
Only later, when Muhammad and his early Muslim companions moved to Medina was the term qital or ‘fighting’ introduced, and here it is made quite clear that Muslims were only allowed to fight to protect themselves (and also non-Muslims who had been attacked) from the prospect of being wiped out. Furthermore, if the enemy stops fighting, Muslims were then required to do so themselves and make peace.
So if you are facing an existential threat, you are permitted to defend yourself.
When it comes to specific verses, their meaning is often contestable. For example, verse 3:151 reads ‘We will put terror into the hearts of the unbelievers….Hell shall be their home.’
Sounds pretty emphatic. However, another way of looking at the verse is in terms of its specific context. It was given to Muhammad just before an important battle, when the early Muslims faced a much stronger enemy. He was worried about the outcome and Allah was basically reassuring him that things would go well. So it was never meant to be a rule for all later Muslims to follow.
Unsurprisingly, the principle of abrogation (naskh) that you refer to has been severely criticised by both early and modern Muslim scholars. One example is the Syrian scholar Wahba al-Zuhayli, who has taken issue with the position that Qur'an 9:5 abrogates 124 other Quranic verses which preach peaceful solutions to conflicts. Here, al-Zuhayli seems to be taking up the position that the Qur'an has to be read holistically, and that the cumulative message is one of seeking peace and only resorting to the use of violence in extremis. Another response has been to explain 9:5 as being context specific. It refers only to Arab polytheist idolaters who were seeking to wipe out the early Muslims, as has already been suggested.
Of course, Salafi-jihadists have their own way of looking at things. Once again, I like what Adam Silverstein says about this in his little book on Islamic history. The additions in square brackets are my own;
'[A] lenient interpretation [of the relevant passages] will certainly appeal to the overwhelming majority of Muslims, for whom jihad is a personal battle against temptation, and who will be drawn into warfare only when provoked by those threatening Islam itself. And even then, innocents will be spared [this is due to rules laid down by the first Caliph Abu Bakr that are remarkably similar to those found in the later Just War tradition of Christianity].....But to extremists, Islam is under attack, a defensive jihad is necessary, and those non-combatants who were killed in the attacks were not innocent at all - in democracies voters bear full responsibility for their government's actions (in this case, Britain's aggression (as they see it) against Muslims in Iraq and Afghanistan)'.
In summary, I reckon that if you have a large enough body of scripture you can inevitably find justifications for your own agenda and causes.
For example, some of the violence perpetrated by Japan in WW2 was justified in terms of a pragmatic Buddhist scriptural concept called upaya-kausalya. Violent manifestations of Christian Liberation Theology also find their justification in a passage from Luke's gospel about 'setting free the oppressed.'
Gush Emunim are no longer around but they would, I imagine, have based their ideology on conceptions of the land of Israel having been given to them by God. And the US anti-abortion movement 'Army of God' (responsible for 8 murders, 41 explosions and 173 arson attacks that caused hundreds of abortion clinics to close in the 1980's and 90's) invoke the 'suffer little children' Biblical passage to justify their actions.
One thing that is clear is that Salafi-jihadists absolutely contort themselves to find theological justifications for what they get up to. As Shiraz Maher puts it in his seminal study, 'The violence of groups like al-Qaeda and associated movements is neither irrational nor whimsical. For every act of violence, they will offer some form of reference to scriptural sources - however tenuous, esoteric or contested - to explain their actions.' It's their perverse way of trying to capture hearts and minds, I suppose.
But anyway, I've got to get on.
If there is something I learned from teaching Religious Studies as an academic subject for so long, it's that it is usually the puritans & literalists within a faith who cause all the problems.
Maybe that's why the irreverent Sufi Muslim poet Hafiz once made this haiku-like observation:
‘The great religions are the ships,
Poets the lifeboats,
Every sane person I know, Has jumped overboard.’