Why any individual is motivated to join the USMC is not why the USMC exists.

Why the USMC is employed to address any particular problem is not why the USMC exists.

To understand why the USMC exists one must study the organization, its history, missions and role in relation to the goals of the US as a whole. The stories of individual Marines, battles and campaigns are interesting, but only lend color, not clarity to the larger question.

We understand this inherently, and yet we continue to agonize over the eaches of any particular individual who decides to throw their support behind a group such as AQ or ISIS in an odd belief that if we understand why individuals join we will somehow be better postured to make the organization as a whole either comply with acceptable social norms or go away in the entirety.

The sum of these many personal stories does not tell the story of why these organizations exist. These stories certainly lend insights, but they equally distract us from reasons much more closely aligned to challenging the activities of those these organizations oppose, than to the promotion of the beliefs or promises these challengers advertise.

Historically there is almost universally a powerful bias of perspective regarding the nature and rationale for revolutionary actors by those these revolutions are directed against. We need to adjust for that bias in our analysis.

Revolutionary activity tends to be far more about the removal of some system of power or governance (often associated with some ideological system of beliefs) deemed as both intolerable and equally something one is now empowered to do something about; than they are about advancing something new and better.

Far easier to get a disparate group to agree that the status quo is intolerable, than it is to get them to agree to some future solution. Thus the chaos that typically follows a wholesale regime change, regardless of how bad or evil that previous regime might have been.

Revolution creates the chaos opportunity is made of - the problem is that so many line up to seize that opportunity, and typically not with the good of the many as their prime directive.