IMHO, much of what was beloved about Frank Castle from the comics came from Garth Ennis. My take on Ennis is he conceived the Punisher as a bad person period. Conflicted yes. Under extreme and impossible circumstances yes. Having horrible unforgivable tragedy thrust upon him yes. But he was always a killer at heart. It was just bad luck and bad circumstances that helped the "mask" of a functional valued member of society ( soldiers are generally respected as a profession, they might not be seen positively in their individual actions, but it's considered generally honorable to serve) fall off. Whereas most superheroes have to face themselves and their demons and put the mask on, Castle never wears one. The worst kind of "mask", the fake inauthentic "civil member of society" falls apart.
Where I find the Punisher Marvel series struggles ( though I love Bernthal in the role) is it constantly tries to justify why Castle is the way he is and looks for a reason to rationalize it. Instead of presenting the complexity and allowing the viewer to decide for themselves, Marvel and The Big Mouse want to force the audience into a very narrow path of exposition, rationalization and explanation.
The Ennis conception of the Punisher does not DEER ( Defend / Excuse / Explain / Rationalize ) but the Marvel TV series tries in every possible way to do so. If you take all that away, the show has the ability to really stretch it's legs. The Punisher doesn't win because he fights monsters. He wins because he's the biggest monster period. There's a huge difference between having a "code" and being too self righteous to be a mobster, drug dealer, child molester, human trafficker, scam artist and grifter POS.
What Marvel did was make The Equalizer instead. ( i.e. Denzel looking for permission and soul searching to fill his heart with enough rage to kill all his cardboard cutout evil beyond all measure enemies) I have no problem with The Equalizer, if you want an ex CIA assassin working at a Home Depot who fights mobsters. But it's NOT the Punisher.
I want to be fair, I don't think one could make a truly honest visceral conception of The Punisher in the current television climate. That scene above, with the face burning, that caused lots of lobbyist groups to threaten FX to change the level of brutality in The Shield, or they would go after all the sponsors/advertisers for the network itself. But Vic Mackey, a corrupt detective, is a more honest conception of The Punisher than the Marvel version. It looks like he has a "code", but he's more offended that some POS child rapist thought he could get away with it on Mackey's turf. Another interesing comparison is a small sleeper show, Mr. Inbetween. Where the main character simply accepts he's not a good person. He does what he does because it's in his nature.
IMHO, here's an unpleasant truth about how people actually behave ( not their virtue signaling, not the crap that's indoctrinated by industry executives and writers who are heavily college educated, sheltered, grew up with money and opportunity, never went hungry and have no conception of how real working class people live and survive) -
It's more desirable to be a bad person who is incredibly good at what they do versus a good person who is totally incompetent but means well.
I just watched Cinema sins on it to refresh my memory.. Eek that's a bad movie. 
