It's really not. D&D alignment is based on real world morality in exactly the same way as hit points are based on real world biology, which is to say not at all except they use a few of the same words. Much as hit points are a fictional depiction of biology created for gaming convenience, alignment is ... well, you get the point.
No, they are nothing of the sort.
Hit points in 5E Dnd are expressly a pool of luck, resolve, the will to live and health. They are also expressly experience and skill (they improve with experience).
Alignment is action-movie morality: it's okay to kill the bad guys because they're bad, now get on with the action.
No, its not. It never has been, and never will be. Alignment has never ever been described in those terms (barring some random quote by Gygax that gets bandied about every now and then, which is nothing more than a statement on his own views on aligment).
Certainly since 3E at the very least, killing, harming and opressing others = Evil. Mercy, compassion and kindess = Good.
And I hate to break it to you, but most 80's action heroes are probably Evil. Antiheroes like the Punisher and so forth most certainly are.
I dont see Luke Skywalker murdering defencless and unarmed prisoners. His old man did against Dooku, but we all know how that worked out for him, and even
he knew it was wrong. I dont see Superman or Batman doing the same.
To you the only difference between Good and Evil is that 'Evil people rape, murder and torture everyone, while Good people only rape, murder and torture evil people'. Its a patently absurd position to have.
Well you are right about one thing. I would only last 5 seconds in your campaign because what the hell kind of BS are you even talking about, attempted murder? I dont even...is this supposed to be DnD or is this Law and Order the board game?
Its a roleplaying game. You're in a tavern in town, and someone pulls a sword on you and attempts to kill you.
Thats attempted murder.
Unless your game world is some kind of theoretical anarchic free for all where there are no laws of any kind, because in every human civilisation since the dawn of time, drawing a weapon on someone and trying to kill them is against the law.
Who are these precious NPCs going to go crying to when the Cultists/Demons/Dragons/Giants come rampaging through their town?
Ahh I see. You're obviously expressing a LE argument here:
(Your PC turns to the patrons of the tavern with a sneer, as he wipes the blood from his sword and a soft bloody gargling can be heard from the dying Bob):
'Listen up. He got what was coming to him. He shouldnt have angered me. It served him right. Remember, you all need me to keep you safe; think on that you worthless peasants. Anyone else have any problems with what I just did, and I'll kill you where you stand too. Then I'll kill your families. Remember, in this town, my word is the law.'