I'm a well read grad student who's bluntly honest about all things, although I try to be most honest about myself.
Frank Castle is on a mission, in War Machine armor. He won't let Fury, corrupt ex-S.H.I.E.L.D agents, or even the threat of war stop him; there are criminals that he has to murder.
I'd forgotten just how much I enjoyed this storyline, but boy, am I glad to be back into this.
The 'I'm your only hope' joke was funny enough, but the fact that Castle didn't realize it was a joke was telling: it's a cultural point that almost everyone recognizes. Castle doesn't because he's single-minded, ruthlessly so.
The humor isn't only funny, it's meant to reveal something about these characters - and it does.