Why did Hitler hate the gypsies?

Hitler hated just about every culture.

Because he lived next to gypsies and they shot his dog

Hitler saw the Romani (incorrectly called Gypsies) as an inferior race of people who were parasitic on the accomplishments of Aryan Europeans. Hitler argued that they were filthy, lazy, and theft-prone. In fact, many of the negative views towards Romani persist to this day in Europe, where it is called Anti-Ziganism or Anti-Romaniism.