The profile shows some rather interesting things Umbridge had in common with Voldemort, namely a Muggle parent and a family she was ashamed of. After her family broke up she never spoke to her Muggle mother and Squib brother again and persuaded her father to retire out of sight – inventing a new deceased father when asked by her colleagues if she was related to the Umbridge who used to work at the Ministry. Umbridge was as desperate as Voldemort to erase her past and recreate herself.
Jo also likened Umbridge to Voldemort in her thoughts after the story.
Dolores…is one of the characters for whom I feel purest dislike…Her 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.