I would disagree with the other commenter as Sykes-Picot does not explain, for example, Ramzi Yousef, a Pakistani, wanting to blow up the World Trade Center.

Your title refers to "events" but then the paragraph beneath refers to some issues like "our excess" and "capitalism" that can't be said to be events. This is often described as the problem of grievance vs. ideology.

In contrast with the other commenter I would certainly not dismiss "the Allah stuff." There is a meaningful ideological difference and substantive difference in outcomes between someone who is inspired by Arab nationalism to fight for the state of Egypt, and someone who inspired by events in the region kills Egypt's head of state.

In explaining this, I would say that "Islamic extremists" is not a very useful term. The most descriptive term, that I think is helpful in understanding these movements would probably be something like Salafi Jihadi Islamists.

This describes three distinct ideological outlooks.

A Salafist is someone who practices a particularly austere form of Islam characterized by an attempt to emulate the practices of Muhammad's immediate successors (the Salaf), rejection of what they characterize as "innovation" (Arabic: bida) in the religion as potentially heretical, and a general attitude towards religious interpretation that favors a kind of direct unmediated apprehension of the sources of Islamic law and so tends to take the Sunnah as more literal and more directly applicable than do other systems of Islamic religious belief or law, which tend to contextualize the Sunnah historically and practically. It's particularly a Sunni practice.

A "jihadist" in this context is someone who holds that violence is an appropriate response to perceived threats to the Islamic community, and that moreover undertaking such violence is an individual rather than collective responsibility of members of that community. For our purposes we can also include in it, though it need not strictly be included, a set of related beliefs about the permissibility of suicide attacks and attacks directed against civilians.

An Islamist is someone who is a believer in political Islam, that is, the application of Islamic precepts to modern state political institutions. That can have an incredibly wide array of meanings and exists on a spectrum. Many governments in the Middle East include clauses in their constitutions that the Sharia shall be the basis of all legislation. If someone were to advocate that in, say, the United States, we could plausibly describe that person as an Islamist, but we need describe the government of Egypt, which has such a clause, as having an "Islamist" government per se. That's in part because Islamism is part of a larger ideological project that typically seeks to make the state ever-closer to the Islamic ideal, so while we might describe the government of Egypt as Islamic, it cannot be said to be Islamist.

Islamism can come in many flavors. The oldest and most prominent Islamist group is the Muslim Brotherhood, which was founded in Egypt in 1928 but today has branches around the world. Other attitudes towards Islamism exist; to briefly mention a 20-year rule example, the Islamic State is particularly obsessed with the immediate restoration of the Caliphate, but that particular idea in Islamism has existed at least since the dissolution of the Caliphate in 1924. Islamism in the context of the Salafi Jihadi trend also tends to be trans-national. It rejects the validity of existing nation states and seeks assistance from the entirety of the Muslim community, wherever they might be. This outlook was perhaps most prominently expressed in the writings of Sayyid Qutb.

Each of these ideological trends can overlap, but may not necessarily. A very large number of Salafists are quietists, who reject engagement in base earthly politics altogether. Jihadism is not a precept of either Salafism or Islamism. Etc.

A fourth trend that is worth discussing insofar as most of the victims of these groups are other Muslims is Takfirism. This is the doctrine that it is permissible to declare another Muslim to be an infidel (kafir) and therefore to kill them.

It’s also worth noting that I’m specifically talking about Sunni groups. Shia attitudes towards America and the west (e.g. the Iranian “Death to America” chant) is a whole ‘nother kettle of fish. In terms of these groups hating the west “so much” it’s worth noting that there are plenty of Salafi Jihadist Islamist groups that are not dedicated to violence in or against the west. This has long been a debate both within these groups and among the national security apparatuses of western countries. Al-Qaeda, for instance, took the path that it did in part because of Osama bin Laden’s obsession with the “far enemy”, as opposed to groups like Egyptian Islamic Jihad that Ayman al-Zawahiri was a part of that wanted to wage jihad primarily against the “near enemy,” that is, the regional regimes of the Middle East.

Likewise, the statute that governs US designation of a particular group as a terrorist organization, 8 U.S.C. § 1189(a), (which I believe is a product of the 2001 Patriot act but is worth considering definitionally) states:

(1) In generalThe Secretary is authorized to designate an organization as a foreign terrorist organization in accordance with this subsection if the Secretary finds that—

(A) the organization is a foreign organization;

(B) the organization engages in terrorist activity (as defined in section 1182(a)(3)(B) of this title or terrorism (as defined in section 2656f(d)(2) of title 22), or retains the capability and intent to engage in terrorist activity or terrorism) [1]; and

(C) the terrorist activity or terrorism of the organization threatens the security of United States nationals or the national security of the United States.

Plenty Salafi Jihadist Islamist organizations don’t make that cut. Which, for example, is how so many members of that movement were able to cooperate with the United States in the Afghan jihad.

Among those that do I would come back again to grievance and ideology. In their own ideological terms, the West is execrable for its own sake. As is, for that matter, the east, insofar as these groups reject their own governments as well.

That’s not to say they don’t lack grievances as well, and insofar as a large number of people are attracted to these ideologies those grievances are worth considering in the context of radicalization.

Radicalization, the act by which one becomes a violent extremist, is not a set pathway. There is no “typical” jihadist as far as social science can determine, though it does seem to appeal to a certain kind of individual. Violent extremists tend to be disproportionately engineers, for example.

Certainly many of these individuals have grievances or triggers that lead them on a radical path. Osama bin Laden, while he participated in the Afghan jihad, did not apparently adopt his particular obsession with the far enemy and America in particular until the Gulf War, in which he felt that Saudi Arabia had been made impotent. He could then point to a litany of grievances in American foreign policy to justify his actions, despite having praised America’s support for the Afghan jihad in years prior. Sayyid Qutb’s views were apparently shaped by in large part by his having been tortured by the Egyptian state, and his hatred of the United States and the West from two years he spent living in the US. His grievances range from the innocuous (he was disgusted by a church-organized dance mixer) to the real (his experience of racism, despite himself being a racist.)

On the ideological side, insofar as these movements have risen in prominence over the course of the 20th century, there are a number of inter-related factors. There has been a general Islamic revival across the Muslim world since about the 1970s. There has also been a Saudization of Islam, as Saudi Arabia has sought to export its particular form of Wahhabi Salafism by funding a huge number of mosques, charities, schools and other Islamic religious enterprises.

A number of events that can be cited as grievances had an ideological component as well. If Arab losses to Israel in 1948 can be said to have propelled a series of pan-Arab Socialist revolutions across the region, Arab losses in 1967, 1973 and the Camp David accords in 1979 helped to discredit pan-Arab Socialism. The secretive cell-structure of the Muslim Brotherhood also in many countries meant that Islamism was a more viable (and often the only) opposition movement. Etc.

So TL;DR it’s really complicated. There is a nexus between ideology and grievance. There are complex issues to discuss on both sides. There is no shortage of reasons why an individual might become a Salafi Jihadist Islamist, and the social science on radicalization suggests that there is no “typical” path to radicalization or profile of a radical.

I've run out of characters so I'll post sources in a second reply.