Why was THIS scene considered as Arthas's step to the path of darkness? He really had no other choice...

You didn't even play the mission : if he doesn't purge it leads to a complete undead victory.

Uther: Glad I could make it, Arthas.

Arthas: I watch my tone with you, old man. I may be the prince, but you're still my superior as a paladin.

Uther: As if you could forget. Yes Arthas, there's something about the plague I should know. ...Oh no, it's already begun. These people may look fine now, but it's only a matter of time before they turn into the Undead!

Arthas: What?!

Uther: This entire city must be purged.

Arthas: How can I even consider that? There's got to be some other way.

Uther: Damn it, Arthas! As my future king, order me to purge this city!

Arthas: I am not your king yet, old man. Nor should you obey that command even if I were.

Uther: Then you must consider this an act of treason.

Arthas: Treason?! Have I lost my mind, Uther?

Uther: Have you? Prince Arthas, by right of succession and the sovereignty of your crown, you must hereby relieve me of my command, and suspend my paladins from service.

Jaina: Uther! He can't just--

Uther: It's done! Those of you who have the will to save this land, follow him. The rest of you... get out of his sight.

Arthas: I've just crossed a terrible threshold, Uther.

Jaina: ...Arthas?

Arthas: I'm sorry, Jaina. You can't watch me do this.

It's not that arthas is wrong that the people had to be purged, it's that he acted like a huge prick about it. Going by the campaign itself it's not even clear if arthas ever explained to uther what the plague even is, as he's not there during the missions where him and jaina figure it out and this mission is "shortly after" uther saves the day.

When he received any kind of pushback against his desires instead of just explaining things he went full retard and told everyone to fuck off. In that moment arthas reveals his character as someone who cares more about getting his way than doing the right thing, that's why kel thuzad says with certainty that they would meet again, because he and/or the lich king had an understanding of arthas's true nature. That's why it's the start to his path of darkness.

Now thats not to be said that uther and jaina aren't in the wrong in that scene as well, that's why it's such a meme. It's a very nuanced scene in an otherwise very straight forward "fight the bad demons" story

Because usually speaking, a normal person doesn't jump in to murder innocent people straight ahead. Even if you know they're gonna turn into zombies, that shouldn't make it easier.

A real paladin would've tried to save them for as long as he could and killed them only when they died.

>if you don't do the mission objectives you lose
no shit

No. I mean the game literally mentions the consequences of not purging the city. I'm not talking about a "game over" screen.

>b-but it was game over if you didn't win

Because Arthas and the kingdom didn't fall and there was no story, faggot. Don't pull this "but in the game!" bullshit unless you concede that Strat only consisted of 12 houses and the number of mobs couldn't possibilty have threatened a kingdom.

Not really true, bloodletters don't burst out the ground in every war zone nor do you grow blue feathers every time you bluff at cards. It's more like the pedophile elites on little saint james are putting on such a show because wish they could be degenerate enough to earn slaanesh's attention.

>if you lose it's game over

gee really faggot

It could according to the game. Strat is the second biggest city and the kingdom was already weak. It's not hard to conceptualize that.

Even if Lordaeron falls, if Arthas doesn't become retarded Ner'zhul doesn't ever get free from his prison, the Legion doesn't get summoned, etc etc...