Por que Umbridge não gostou de Harry desde o começo?

A história de Umbridge em Pottermore publicada em novembro de 2014 deixa claras três razões para sua perseguição de Harry Potter:

1. Ela se apegou a Cornélio Fudge politicamente, e (como sabemos nos livros) Fudge's Party Line era que Dumbledore pretendia desalojá-lo como MoM, e Harry era um garoto mentiroso servindo esse fim com suas mentiras sobre "Aquele que não deve ser admitido para ter retornado".

   Em essência, desacreditar Harry seria uma grande vitória para seu patrono Fudge, e vice-versa.

   As the Minister for Magic Cornelius Fudge became increasingly anxious and paranoid that Albus Dumbledore had ambitions to supersede him, Dolores managed to claw her way to the very heart of power, by stoking both Fudge’s vanity and his fears, and presenting herself as one of the few he could trust.

2. Umbridge odiava muggles e trouxas.

   Como tal, Harry era uma coisa ruim ambos como meio-sangue, E como um símbolo para aqueles que tinham opiniões pró-trouxas e anti-intolerantes.

   After a glass of sweet sherry, Dolores was always prone to spout very uncharitable views, and even those who were anti-Muggle found themselves shocked by some of Dolores’s suggestions, behind closed doors, of the treatment that the non-magical community deserved

3. Umbridge era um freak de controle , que viu Harry como um desafio para sua autoridade , e sua resposta a tal desafio foi acabar com isso:

   Dolores’s appointment as Inquisitor at Hogwarts gave full scope, for the first time in her life, for her prejudices and her cruelty. She had not enjoyed her time at school, where she had been overlooked for all positions of responsibility, and she relished the chance to return and wield power over those who had not (as she saw it) given her her due.

   ...

   Dolores has what amounts to a phobia of beings that are not quite, or wholly, human. Her distaste for the half-giant Hagrid, and her terror of centaurs, reveal a terror of the unknown and the wild. She is an immensely controlling person, and all who challenge her authority and world-view must, in her opinion, be punished....

Ela não o odiava pessoalmente. Ela só estava tentando fazer o trabalho dela e honestamente ela era meio malvada.

Wikia Dolores Umbridge:

Umbridge was also a cool-demeanoured sadist who rarely expressed the extent of her anger openly, casually making decrees and handing out torturous punishments with a smile (most notably, forcing Harry to carve "I will not tell lies" into the back of his hand with a Blood Quill). She created several new rules and regulations in order to increase control and chances to punish students, despite many of them being ridiculous and unfair.

O Ministério enviou-a para fazer um trabalho específico, se ela não tivesse completado, ela estaria em apuros e teria perdido algum de seu poder. Pela citação a seguir podemos ver que ela não gostou disso. Ela exerceu seu poder ao máximo, quero dizer, quase matou a professora McGonagall.

She was depicted using any means to maintain her personal power and the political power of her bosses. She committed attempted soul-removal (via the Dementor attack on Harry), solicited bribes, and tortured children to achieve her goals.

E ela até odiava a própria família.

Her younger brother was a Squib but she herself was born a witch. Under her father's influence, she despised her Muggle mother and her Squib brother, considering them inferior to her and her father, and they both denounced them.

Realmente não era só Harry, ela odiava todos que não tinham poder para impedi-la. Foi porque ela se sentiu mal consigo mesma.

Following Voldemort's takeover of the Ministry of Magic in 1997, Umbridge resumed her post as Under-Secretary and oversaw the registration and persecution of Muggle-born witches and wizards. She conducted trials with sadistic pleasure, subjecting innocent Muggle-borns to the presence of Dementors and sending them to Azkaban for supposedly stealing magic from "real" witches and wizards

Os Fóruns do Cos têm algumas implicações interessantes.

Do usuário Fellyphone:

I think the original reason why Umbridge had a beef against Harry had to do with her wanting power and she saw Harry as a threat because he associated himself with Dumbledore. Rather than get rid of Dumbledore right away, she sought to discredit Harry and to wreck havoc on his summer by sending out the dementors.

Harry nunca calar a boca sobre o que aconteceu e isso minou sua autoridade, uma vez que ela deveria "parar as mentiras" e fazer as ordens do Ministério.

Do usuário Saiorri:

I think like a lot of other people, especially the ones who wanted to discredit Dumbledore, Umbridge wanted to silence Harry just to prove he's human and not "The Chosen One." Umbridge didn't have to know Harry to discredit him. He was trying to tell everyone that LV was back, when the Ministry was saying LV was a done deal from over a decade ago. I was just talking to my mother about this the other day. Imagine, if you will, that we didn't know that Hitler shot himself instead of being defeated by his last victim, and we didn't have a body to prove he was gone, and then some kid claims "Hitler" did some murders in Israel in 1958 and he was there-----if you lived in Israel, would you want to believe he was back?!?! ......

Precisamos lembrar, ela tinha o colar de Voldemort em volta do pescoço ... lembra o que fez com Ron, Harry, quando o vestiu? Quando Harry entrou na piscina para buscar a espada, tentou matá-lo ... por isso deve-se argumentar que poderia ter tido um efeito estranho nas Dolores, não apenas querendo silenciar Harry, mas talvez até matá-lo junto com Dudley.