Of course Abraham believes he's right. Pretty much everyone believes they're right. (Even John Manuelito!) I'm not saying he doesn't have a point, I'm saying that he's blinded by his own biases and history, too obsessed with revenge to think clearly about how his (stated) goals might best be achieved. A complex figure, yes, but definitely firmly in the "Evil" portion of D&D's limited alignment system.

Italy was an enemy nation filled with actual soldiers; the Tirpitz was a battleship. We are talking about the deaths of civilians here, so your analogy does not hold. There is, of course, a good chance sealing the Lands Below was the most efficient way to deal a huge blow to the Confederation, but even at this early stage I have a hard time believing it was "necessary," even if I thought violent revolution was the only way to bring down the Deathly Regiment (which again, I don't).