You bolded the line where his father snatched the dose out of his hand. while underplaying the line a few lines down where 14 year old klaus agrees to betray the girl who just went through so much to give him a cure. So that his dad can sell it for an even better cure.
here:
sure, he did not INITIALLY plan to betray alice.
Alice gave him a cure and he planned to use the cure.
But then his father snatched it from his hand, asked him what it was for, and asked 14 year old klaus to betray alice and in return for that betrayal klaus will get an even better cure and become strong.
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this is a classic abuser line.
"she made me hit her"
Also at this point Klaus is a superhuman and his family is already at the top.
where he ordered a hit on alice's family who were way weaker.
And you are also glossing over how he justifies his family betraying those who have helped his family before so they can rise above them. returning kindness with backstabbing.
If I tell you to ask your mother for some peanuts because I get dizzy and I need some minerals, and I use the peanuts to kill your father who has a peanut allergy, is that result your fault? While you could say that giving peanuts is different to giving some secret drug and we tend to view Alice's actions like some great benefactor who moved heaven and earth for her friend, this is what really happened:
Alice gave him the medicine in the first place out of spite for her father.
Michael "Your dad would kill you if he heard you say that."
Alice "Well he's not here, like always."
And all Klaus was asked to do, is get some more. This simple action would elevate both him and his family.
Klaus never knew that his action will contribute to Alice getting alienated.
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You are wrong about the "classic abuser line":
"And just like I had hoped, my dad was ecstatic."
"We traded both serums and were welcomed into their inner circle."
"With a seat on their council, we had more than enough sway to carve out our own piece of the sector, to break our ties with the Alderman."
"I heard you didn't take the news too well and ended up injured in a skirmish with our men. That was the beginning of your illness, correct?"
You are also wrong about Dietz retiring.
Klaus is still the second in command at this point. Dietz never left the family reigns to him.
Klaus has his own ideas about how things should be, and at this point he has turned full villain, but he still carries his father's will.
It's obvious that the "inner circle" refers to Langdon's organization and Dietz is the one with the chair.
He could have said "I am sorry, my dad decided to do that, and he was wrong"... except, he couldn't really because at that point his dad was already retired and he was the head of his family.
There is nothing to ask forgiveness for if Marcus was the one who attacked first. Marcus never disputes this and Klaus mentions it twice, both to Alice and to Markus.
Marcus is a criminal and the "kindness" you speak of is a fairy tale. Uplifing a crime family and forcing them to do even more terrible things in return can hardly be called kindness. For all we know, Dietz could be completely justified. I doubt that this was exactly the case but it's not out of the question.
Marcus is a piece of shit and if he was the aggressor like Klaus claims (which most likely is the case) then the burden of proof falls on him.
His twisted views of love are irrelvant.
Here you show that Klaus firmly believes he did nothing wrong.
This is him showing no remorse and seeing no problem with his actions.
Maybe you will get it better with a fiction analogy?
... how about... kartman from south park?
You notice how kartman is shown as believing in his own bullshit? How every time he "recalls" a scene it changes to show himself at a better light?
When Klaus goes "I just wanted to be strong for my family and you" and so on, he is showing zero remorse for betraying her. and insisting he was justified all along.
How about you apply this to Alice too?
If anything, Klaus idea of "getting strong for family's sake" is more mild than Alice's.
How many people did Alice kill while searching for a cure for Marcus, both Aldain and Alderman.
How many people did Alice kill even after taking her revenge on Klaus, out of spite?
And you'd think that Klaus is the delusional one who just stole something that was given to him out of spite in the first place?
The chain of events is a bit complicated and everyone involved is a piece of shit probably in need of serious psychiatric help. But this is what plausibly happened based on dialogue:
Alice out of spite gives medicine to Klaus
Dietz finds out and asks Klaus to get some more, in return he will be given the world as reward and improve his chances with Alice (in his mind at least).
Dietz trades the medicine and his family breaks into the big leagues (joining Langdon and the rest), breaks ties with Aldermans.
Klaus is given his reward.
Marcus attacks the Aldains and gets mortally wounded.
All hell breaks lose.
We don't know what would happen if Marcus could just let it go. Perhaps the same thing would happen, perhaps not. But blaming Klaus for this when we had manipulations, multiple betrayals (including Alice betraying her father out of spite) and dick measurement among hardcore criminals who don't care about death, torture and human experimenetation, is blowing it out of proportion.
And the point here isn't to make Alice seem worse. It's to so that what you call "betrayal", can also be a "simple mistake" or anywhere in between.
I agree that current Klaus is power hungry and a true criminal, but this doesn't apply to old Klaus and I don't think that any of his peers would ask for forgiveness if they were in his shoes. Neither I'd expect them too with the knowledge they had at the time.