We could also say that the knights' true goal was not to beat out Muslims from the Holy Land, but to use the opportunity to gain feudal lands for themselves. The pillaging on the road to Palestina (especially the overthrow of the remains of the Byzantine Empire, but also everywhere else) also supports that view...

Regarding general history of Christianity vs. Islam, some things to consider:

• You more seem to think of Western Christianity, yet the Eastern one in the Byzantine Empire and Armenia had a history of confrontation with the empire(s) of Mohhamed and his successors practically from the first decades.
  
• Western Christian countries first had major conflict with Islamic rivals when the latter took over the Iberian Peninsula, and their invasion of France had to be stopped.
  
• Still in the First Millenium, even the hearthland of Western Christianity, Italy, was raided, and there were fighting Popes who led armies themselves.
  
• The Holy Land was not a core area of Islamic empires. What's more, thechallenge from the Crusades was dwarfed by conflicts like with the Mongols. Until 19th-century European imperialism and the I/P conflict made all cultures focus on this history, for Islamic cultures, the Crusades were more like peripheral squirmishes.
  
• Christian countries (both East and West) got their biggest Islamic challenge with the rise of the Ottoman Empire. This empire first at up the remains of the Byzantine Empire, then the Balkans, then when Crusades started against them failed, subjugated the Hungarian Kingdom and the Tatars in what is now Ukraine, and then was an existential danger for Venice, Austria, Poland/Lithuania and Russia for two centuries, fighting several major wars (on the scale or larger than the Crusades against the Holy Land) against each of these.
  
• Note that the Ottoman Empire also subjugated most Arab lands.
  
• Also note that beyond the Crusades for the Holy Land, against the Cathars, and against the Ottoman Empire, there were also ones against the Slavic and Baltic pagans that remained between Russia and the German empire. (Lithuania was born from a defense alliance against such one, and was so successful that it grew into a short-lived empire, going Christian voluntarily in the process.)

_{*Lunatic*, n.
One whose delusions are out of fashion.}