The Crusades, and even the Inquisition, were and are not central or major tenets of Christianity as a belief system. You are persisting in attempting to understand Islam as an Anglican might attempt to understand a Methodist.
Freefly, that isn't going to work for you. JIHAD is THE foundation of Islam.
In regard to American Muslims: if they want to live here, they must follow our laws. That would mean that they must abandon many of the beliefs and practices of their religion: e.g. JIHAD, polygamy and female circumcision. Our laws say we must tolerate all religions, And in regard to Islam, Official America looks the other way.
However, it would be absolute folly to expect them to tolerate us as we do them.