Always Wondering: Why Is Fighter's 2nd Job Called Crusader?

Page - White Knight - Paladin line already absorbs all of the "holy/medieval warrior" flavor.

Transitioning from Fighter - Crusader - Hero seems somewhat odd.

To me, the Fighter role is more like an anime or game protagonist, similar to 'the Hero' in Dragon Quest or Link in Zelda, and doesn't really have a knight/holy/religious connotation in their kit.

Fighter use combo attack which is just like some ancient fighting technique that is pass down to them by a master.

With that sense, calling 2nd job "Chanpion," "Gladiator," or "Vanguard," sounds more fitting to me.