Umbridge was xenophobic and intolerant towards Half-Breeds as well. Because of this, she was extremely impertinent and argumentative towards Rubeus Hagrid, the Gamekeeper and Care of Magical Creatures professor, and antagonized him as he was Half-Giant.
Dolores Umbridge has been called one of the most despised fictional characters of all time due to her authoritarian stance and dictatorial presence, as well as her racist attitudes and torturing of children.
Apparently, Umbridge's mother was a Muggle and her brother was a Squib – a source of huge embarrassment for the family. Perhaps their abandonment and retreat back into the Muggle world had such a huge impact on Umbridge that it became the catalyst for her Muggleborn-targeted cruelty later on in life.
The only problem is that she tends to overdo it to the point that it's just as disconcerting. All in all, she's an “amazing” (as far as sociopaths go) example. And as Harry points out, she's arguably just as bad as, if not worse than, any Death Eater.
With the fall of Lord Voldemort, Dolores Umbridge was put on trial for her enthusiastic co-operation with his regime, and convicted of the torture, imprisonment and deaths of several people (some of the innocent Muggle-borns she sentenced to Azkaban did not survive their ordeal).
The REAL Reason the Weasleys Are So POOR (They're CURSED) - Harry Potter Theory
Did Umbridge abuse Harry?
She showed a particular hatred for Harry Potter, as she had no qualms about violently punishing Harry during detentions (though it is possible Fudge told her to be harsh on him).
A Ministry of Magic bureaucrat who was able to indulge in her sadistic tendencies when she was posted to Hogwarts as Defence Against the Dark Arts professor, Dolores Umbridge was famous for her sickly pink wardrobe and her particularly violent taste for corporal punishments.
In turn, Umbridge acts in the open, from a position of power, being the Minister of Magic's right hand. She's not a Death Eater masquerading as a government official — she's just an awful person taking advantage of being in a top position.
Although Umbridge was not a Death Eater, and had no direct contact with Lord Voldemort, she showed that she was fairly in line with their goals. This was due to Umbridge's callous nature and her prejudiced beliefs, both of which were similar to Death Eater behavior.
“[Umbridge's] desire to control, to punish and to inflict pain, all in the name of law and order, are, I think, every bit as reprehensible as Lord Voldemort's unvarnished espousal of evil,” Rowling wrote.
It takes a lot for a character to be hated more than the franchise's main villain, but the sheer vitriol that fans feel for Dolores Umbridge certainly does the trick.
Well, in Umbridge's case, while she may have been working for the bad guys of bureaucracy, she was never under Voldemort's thumb. She was allied with the Death Eaters and definitely enabled them, she was never an official part of the organization.
If you have only seen the films, you might be surprised to hear that it wasn't Cho Chang who betrayed Dumbledore's Army to Professor Umbridge – it was Marietta Edgecombe. A friend of Cho's and a fellow Ravenclaw, Marietta (reluctantly) joined the DA.
Luna married fellow naturalist Rolf Scamander, grandson of Fantastic Beasts and Where to Find Them author Newt Scamander, considerably later in life than Harry, Ron, Hermione, and Ginny, who all married and started families in their early-to-mid twenties.
Why did Dumbledore not fire Umbridge even when he knew that she was teaching poorly? Because Umbridge had been installed by the Ministry and wasn't hired by Professor Dumbledore. Due to Educational Decree 22, if the headmaster couldn't find a teacher for a subject, the Ministry could then appoint someone.
Hagrid's half-giant status also meant that Umbridge was highly prejudiced against him, viewing him as a "filthy half-breed", and so she became quite determined to get rid of him. Umbridge's biased and insulting inspections of his classes made Hagrid rather nervous, and he was soon placed on probation.
Bellatrix was an unapologetic monster who utterly relished in the pain and torment she caused, Umbridge was a monster but a monster in a pink coat, she could hide her evil behind a fake smile and supposed civility.
As Dolores Umbridge was a sadist who enjoyed torturing students, Filch could relate to this. Also, as Umbridge granted Filch permission to torture misbehaving students, whereas Dumbledore would never even think of such things, he had loyalty to her. He is the only person who liked her at the school.
They are just as vile as each other. The key difference is that Umbridge has more control being able to mask her " evil " and be in a government position where as Bellatrix is the person that has been caught and is more impulsive.
J.K. Rowling has answered this question with one of her new stories on Pottermore. In her history of Dolores Umbridge, she stated that Umbridge was in Slytherin.
Peter Pettigrew (a.k.a. Wormtail) is one of two Death Eaters known to have been in a House other than Slytherin (Gryffindor) while at Hogwarts. There, he was a close friend of Sirius Black, James Potter, and Remus Lupin, although he was the least intelligent and least talented of the group.
Harry Potter was one of the students upon whom Umbridge frequently forced this punishment, since he persistently claimed that Voldemort had returned during the Defence Against the Dark Arts classes, which the Ministry of Magic refused to believe.
Actually, Umbridge was inspired by one of her teachers. That's how she is written in the books. The idea is to make her as grandmotherly as possible in appearance: all pink, kitten plates, a bow on her head.
Why wasn't Dolores Umbridge ever afraid of Albus Dumbledore? Because, being a complete nut-case, she falsely believed Dumbledore could never hurt her. > “The Chair recognizes Dolores Jane Umbridge, Senior Undersecretary to the Minister,” said (Cornelius) Fudge.
Umbridge has always had a strong hatred towards anyone who wasn't a pure magical human and, as previously mentioned referred to Centaurs as "filthy half-breeds." She was also the head of the Muggle-Born Registration Commission, where she was in charge of interrogating muggles who she believed 'stole' their magic.
