good answer
and the crusades were not Christian
The Crusades were expeditions undertaken by the Catholic Church, in fulfilment of a solemn vow, to deliver the Holy Lands from Mohammedan tyranny. Oh and by the way Catholics are Christians.
The Crusades were defensive movements aimed at reclaiming the Christian holy places seized by the Muslims and freeing the hundreds of thousands of Christian captives kidnapped by the Muslims.
One of the big problems was that the European rulers were too busy fighting with each other to really get behind the idea, and when the Pope appealed for forces, after the First Crusade, it then became increasingly the rule to hire mercenaries and also allow them to take booty as compensation. The famous sack of Constantinople was because the Byzantines had actually hired these mercenaries themselves but then did not pay the mercenaries what they thought they were due, so they sacked the city.
Horrible, but it was not because the fundamental reason for the Crusades (to retake Christian lands and free Christians) was wrong. It was mostly because of European politics.
“and the crusades were not Christian”
They most certainly were.