The way I saw it, DD was going through a personal crisis of faith. He not only turned away from God (for the time being anyhow), but he was willing to walk away from his life as Matt Murdock altogether. In his then-current frame of mind, it wouldn't have made much sense for him to continue espousing a "no kill code" with the same kind of reverence he'd shown in the past. But, as we eventually saw, with his faith in both God and himself restored, so too were his views on the preservation/sanctity of life. That's why he ultimately couldn't go through w/ killing Fisk in the season finale.
I hear you, though. Trying to maintain a code like that all the while practicing such violent methods does seem a tad paradoxical. Still, there's something compelling in the struggle to keep yourself from falling into the abyss when you're standing so very close to the edge. And for me, it isn't about coming short of that goal or even looking like a hypocrite in the process; it's about believing in something worthwhile and continuously trying your best to live up to it.
Fair enough. I haven't watched those cartoons, but I'll take your word for it.
I just hope the character continues to evolve so we get to see more of his personality come through. That way, he wouldn't come off like such a Batman doppelgänger.