Not all of the Roma/Romani people are all bad, of course. It's just the thieving gypsies that bring about so much hate.
I'm from Croatia originally, where we've had them for centuries. Millennia, even.
They're like an organized travelling mafia/sideshow circus. They send children to panhandle, preferably young and cute, innocent looking and dirty, who then give the coin to the person in charge. They have organized "thieving days" and prostitution is very common, particularly among the younger girls. Then one day they just decide that they need to move...
Obviously not all of them are like this, but holy fuck are some of them weird.