While it was nearly five centuries from the death of Mohammed (A.D. 632) until the 1st crusade (A.D. 1095-98), the 1st crusade was called in response to specific and growing outrages in the decades of the 11th century. So, yes, it's true that there wasn't any 'crusading' response to the original Muslim conquest of Palestine, but as the 11th century progressed the oppression of Christians in Palestine became more and more extreme. Destruction of the Christian Holy Sepulchre and all other Christian establishments in Jerusalem after A.D. 1009 could be consider a little bit intolerant, don't you think?
BACKGROUND (until 1096)
http://lexicorient.com/e.o/crusades_05.htm
SUMMARY: There was already a history of tension between the Christian world and the Muslim world going centuries back in time. Until now it had been fought mainly in Spain and Sicily, but with the change of rulers over Jerusalem in 1070, the treatment of pilgrims to the holy city became so bad that Europe reacted. Still it took a couple of decades before the reaction came - the crusades.
800: Ambassadors of caliph Harunu r-Rashid delivers to the Frankian king the keys of the Holy Sepulchre together with other religious gifts, recognizing a Frankish protectorate over the Christians of Jerusalem.
9th century: Churches and monasteries are built in Palestine at the Frankish king's cost.
1009: The Egyptian Fatimid caliph, al-Hakim (who by the Druze is considered as their founder) orders the destruction of the Holy Sepulchre and all Christian establishments in Jerusalem.
1027: The Frankish protectorate is replaces with that of the Byzantine emperors, who start rebuilding the Holy Sepulchre.
11th century: Pilgrimage to Jerusalem becomes increasingly popular, both by priests, monks and nuns as well as common people.
1054: The emperors of Constantinople splits from the pope in Rome.
1070: Jerusalem is conquered by Seljuq Turks.
1084: The strategically important city of Antioch falls to the Seljuqs.
1095 March: Facing the advancing Muslim control over Asia Minor, pope Urban 2 of Rome calls for a crusade, in order to bring Jerusalem back under Christian control and stop the Muslim dominance in the region. This call is heard all over central Europe, and especially in the Frankian regions (corresponding to modern France).
— November 27: The crusade is proclamed at the Council of Clermont.
apparently the writer of this film has also written a film about the Barbary War called 'Tripoli' due out in 2007. Intereting how that's received since no on ever seems to talk about that war.
True. I was not trying to imply that there were no abuses going on in the Holy Land in the 11th century, just pointing out that the region was under Muslim control for around 500 years by the time the crusaders got there, so "onslaught" maybe isn't the best term (though it works fine for the encroachments in Anatolia which compelled the Byzantines to call for help).
For that matter, the original Islamic conquest of Palestine and Egypt was not particularly bloody, and it seems that many of the citizens weren't particularly attached to their previous rulers (Byzantines) anyways. By the 11th century, as you point out, relations between the Muslim rulers and the other people of the book were not going so well, partially due to political instability in the Muslim world.