I will take a part of extended explanation on link below that I think has best answer to your question.
JK Rowling herself has drawn a likeness between the pure-blood fanaticism of Voldemort and his Death Eaters, and the Nazis' anti-Jewish bigotry. On her website, jkrowling.com, she writes:
"The expressions 'pure-blood,' 'half-blood,' and 'Muggle-born' have
been coined by people to whom these distinctions matter, and express
their originators' prejudices. As far as somebody like Lucius Malfoy
is concerned, for instance, a Muggle-born is as 'bad' as a Muggle.
Therefore Harry would be considered only 'half' wizard, because of his
If you think this is far-fetched, look at some of the real charts the
Nazis used to show what constituted 'Aryan' or 'Jewish' blood. I saw
one in the Holocaust museum in Washington when I had already devised
the 'pure-blood,' 'half-blood' and 'Muggle-born' definitions, and was
chilled to see that the Nazis used precisely the same warped logic as
the Death Eaters. A single Jewish grandparent 'polluted' the blood,
according to their propaganda.
You can drawn comparisons between Death Eaters and Nazi followers, or, more tellingly, between Hitler himself and Voldemort. We learned from Harry Potter and the Half-Blood Prince that Voldemort had a Muggle father and a witch mother, and that during his childhood in a London orphanage, he learned to control and exploit others. Prior to Dumbledore inviting him to Hogwarts, Tom Riddle, as he was known then, took fellow orphans Amy Benson and Dennis Bishop down to a cave where he allegedly tortured them.
According to a CIA analysis of Hitler, he came from "illiterate peasant stock derived from a mixture of races. His father was illegitimate. . . Hitler's mother was a domestic servant. It is said that his father's father was a Jew and it is certain that his godfather was a Jew." Other similarities Hitler had in common with Voldemort included megalomaniacal tendencies and "a fixed determination to repress [feelings of weakness, timidity], and to condemn them in others." Hitler, too, insisted on always being right, with enormous discrimination towards others and an appetite for power. As a tyrannical leader who behaved without conscience and who authorised followers to do the same, Hitler, like Voldemort, could be regarded as having a psychopathic personality.
You can look at this link for more extended explanation about ties between Nazi and Deatheaters.