Cute people are going gray area with Castle to defend him but they forget in doing so they open his victims to same treatment. Punisher is villian pure and simple, Punisher doesn't not take time to tell the difference between lifelong criminal who will never change and silly henchmen who is going go to jail for 6 months on because it was his first offence and never do crime again. Punisher( and Wolverine to be fair) regularly kill guards and henchmen who shouldn't die. With Wolverine at least it is uneven writing to blame, with Punisher that is what he does there is literally pic in here from Civil War where Punisher says they were Thieves and Killer. Punisher is fine with killing someone who steals.

I am perfectly fine with Punisher killing but what makes him villain and not antihero like say Wolverine (when correctly written) is that Wolverine is fine with violent criminals being put in jail, Wolverine will not just slaughter every criminal like they are all the same. Before the made a Punisher show, I would describe Punisher show as a "Superhero Dexter" show and I realize now that is incorrect because Dexter is actual antihero and Punisher is much worse. Dexter actually selective picks his victims who deserve to die and no innocents get killed. Punisher frequently kills people who aren't murders,rapist,etc aka crimes that hurt directly people. Punisher kills the stupid person who joins a gang because their friends are in it,Punisher kills person who grew up poor thinks that gang life is the only life. Punisher kills people who would sit in jail for 5 or 10 years who won't go back to crime. That is why Punisher is a villian.