What motivates terrorists?

Schneier on terrorist motivation, positing that it’s less about achieving political ends, and more about being part of a social structure [brunns]. Sounds quite reasonable. I was struck a bit by this sentence:

We also need to pay more attention to the socially marginalized than to the politically downtrodden, like unassimilated communities in Western countries.

Now, I won’t argue with that, except: aren’t they often the same people?