Why do Christians fight in the others war?

The clash of civilization becomes more and more reality. The west creates new enemies to enrich their incomes either governmental or private. Why Christian indulges themselves in Muslims / Jews war? No body hates US because of freedom, democracy and institutional values as they the entire time saying. But in fact it is matter of Israel and alliances / support from the west to this called Israel!!!! After early Muslims conquers, crusades and imperialisms era new page should be open between the two civilizations. But apparently, Christians needs all the time a new enemy……