Why were the Gypsies persecuted by the Nazis?
Many viewed Gypsies to be 'asocial' as they mostly kept to themselves from country to country not adapting to any particular culture. This mostly resulted in Gypsies being segregated from the rest of the population. The Nazis viewed Gypsies to be inferior as well as racially inferior. In camps doctors would conduct test on Gypsies to find a certain 'gene' which proved that they were different.
A scheme like the one Hitler put in place relies on thuggery and intimidation gypsies are a convenient group for his thugs to practice on, as they were only very loosely connected with the local community's and were most definitely looked down upon. Most felt that their areas would be better of without a Gypsies camp nearby messing up the place. and most people were themselves intimidated by Hitlers tactics. keep in mind that the concept of human rights just did not exist in those days. All revolutions are accompanied by intimidation and fear, and this is how Hitler worked.