There is a big difference between warriors in groups dubbed as Holy, and Monks who do some MA training. The Crusaders mostly weren't monks in any meaningful sense of the word, but they were people who were professional soldiers, or were under the command of professional soldiers. Monks spend most of their time in prayer and devotional duties, or duties to sustain themselves. They weren't some group of skilled fighters who led the charge. Battle hardened men with experience of warfare did that.