I think we should have a look at the actual situation among the Romani people, both historically and currently in Europe.
During the plagues, the Romani had a lower death rate due to their strong customs for cleanliness and hygiene, combined (I suspect) with their nomadic lifestyle reducing their contact with rodents. So, of course, people assumed they were in league with the Devil, and anti-Romani sentiment really got going during this period as a result - the anti-settlement laws began. This is similar to what happened to the Jews in this period. In fact, it is estimated that the lower death rates among Jews due to their cleanliness was more than offset by the numbers massacred by those assuming they were in league with the Devil. I expect the same is true of Romanis.
So discrimination against them quickly became entrenched. They were hunted for sport in Saxony, and in many European countries killing a Romani wasn't illegal. In fact, France, Prussia and other countries used to hang them. In much of Eastern Europe they were enslaved to the landed aristocracy. Young Romani were branded like livestock. They were generally emancipated during the mid-1800s, about the same time as the Africans were emancipated in many other countries. Nevertheless, entrenched discrimination of course remained, as with the Africans, combined with the damage it had done to their society and culture, again the same as with Africans in the USA.
This prejudice continued well into the modern era at an institutionalised level. Most European countries have carried out forced sterilisation programs on the Romani. They have been denied the rights to land and the rights to work, excluded from urban areas, and so on. Forced sterilisation went on in Norway until the 1970s, in Czechoslovakia until 1991 and so on. During the Holocaust many Romani were killed. Estimates range from 220,000 to 2 million. Even the lowest estimate would make it one of the largest mass slaughters in history.
In the present-day, there is still massive discrimination, often even carried out by state agencies. In Romania many Romani live in slums on the edges of towns, often because the town governments evict them from their homes in the town, where they had jobs, lives, education and so on, for no reason other than their ethnicity. All Romania's main political parties slander them. They are hugely stereotyped as lazy, dirty and so on. In some examples, the Romanian townspeople cheer on the town mayor as he authorises the building of walls around Romani areas. Nobody bats an eye.
They are generally described as being an endemically-criminal community. People say that 'they' are thieves, beggars, whatever. Yes, crime rates are higher among them than the average in many areas, and there are big problems in their community with Romani gang lords who keep Romani children locked in sheds at night and have them pickpocket all day. And yes, there are big issues in some Romani communities with child marriage. But saying that Romani are thieves and child-abusers and so on is like saying that 'blacks are criminals' because the crime rate within the African-American community is higher than the national average. A lot of the rhetoric against the Romani today is basically the same as the rhetoric against them, and against the Jews, just leading up the Holocaust.
Many Romani do become involved in petty theft now and then in Eastern Europe. When you are forced to the edges of towns, into slums, out of work, when people spit on you in the street, it is hard to get work. So it's starve or steal. There are Romanian Romani people who come over on a coach to London, sleep in doorways or under bridges, and do begging, or try to find work on building sites if they can, so they can bring money back home to build a house for their children. Because they can't get work in Romania, because people really do dislike them. It's very common for an Eastern European employer to throw out a job application with a Romani name. Obviously not universal, but very common.
But Romani are murdered in hate crimes pretty commonly, they get beaten and raped by antiziganist groups in Eastern Europe, they get spat on and attacked in Western Europe too.
For many centuries, the Romani have been marginalised, isolated, excluded, and so no wonder they often feel entirely disenfranchised from the state apparatus. This sentiment can lead to greater crime rates, and less social cohesion. Obviously. Continued discrimination, stereotyping and victim-blaming is only perpetuating this vicious circle.
Final point, on integration. This seems to mean different things. If we mean economic integration, or political integration, sure. That needs to be done. They need to become less marginalised, and measures need to be put in place which can really work to improve their genuine access to education, their living conditions, their awareness of issues like environmentalism and the use of contraceptives. And also to improve their ability to become politically engaged and establish representation. But cultural integration, as I suspect many people mean? The loss of their heritage, their identity, their language or dialect and their customs? Why should they? They have been in Europe for almost a thousand years. In the UK for over five hundred years. Why on Earth should they be forced to lose their heritage and customs to be replaced by that of the dominant ethnicity? Obviously if they want to settle, become stationary, live in a flat or a house, settle in an urban area or wherever, that's fine. But if they don't want to, there's no reason they should. If they want to keep living as travellers, that's perfectly OK, that's their traditional lifestyle, and governments here in the UK and elsewhere should keep working to make sure there are adequate provisions for them to do so if they want.
