Protecting yourself is self-defense by the very definition of the term. Being a warrior means much more than being able to protect yourself. It means being willing and able to protect others as well as yourself. Warriors feel a sense of duty to protect those around them where the ordinary man only feels the need to protect himself. There is a big difference in the two.
The warrior is willing to put his well-being on the line for those he loves or for those under his protection. Many times, he puts their well being ahead of his own. He could easily defend himself and leave the danger behind, but he chooses the path of chivalry and warriorship.
He knows there is a difference between self-defense and warriorship, and he also knows that the lifestyle that he has chosen demands that he put his warrior ideals over simple self-interest. Protecting yourself is self-defense; protecting others is warriorship.