Well, that might be a slightly absurd statement, X.
It could be said that all a dog knows it loyalty, which means that they never stop being loyal.
It could be said that all Paris Hilton knows is being a rich, dirty, soiled , which means that she has constantly been connected to these attributes.
Now, can it be truly said that all he knows is killing or converting infidels?
Pray tell, X, how many infidels has he killed in his life? How many has he converted?
It would seem to me that it is all he knows in a similar way to it being said that all Yonivore knew in highschool was wild hot sex with the head cheerleader. Which, in this case, means that it is something they so desperately wanted, and told everybody else that they were doing all the time.
You might want to back down from that claim.