Why did many Europeans need to go on crusades?

Western Europe was overpopulated during the Crusades. There was not enough land for everyone. The people were beggars. The Catholic Church quickly realized that it would be useful to send a huge number of “hungry mouths” to the East to increase its influence there. The official reason was the oppression of Eastern Christians and the seizure of Christian shrines by Muslims. The poor were promised forgiveness of sins and their colonization of fertile lands in the East. The nobles were also promised forgiveness, but the management of those lands. Rich booty was promised. In addition, a representative of the royal family of each country had to manage his army. Thus, the church increased its influence in Western Europe.