'How is wanting to live with three generations of your family dangerous as speeding in a car would be?'
It isn't, math, unless you break the law and expect others to pay for it. Plenty of people do it here, without breaking the law and expecting others to pay for it.
Oh, back to 'No blacks, no dogs, no Irish' again. Yes, that's a reason why people, whoever they are, should be allowed to do whatever the hell they please, because in the past, governments/societies/nations, were racist and legislated that. Mea culpa, no matter if people living now had nothing to do with the past, they should atone by setting aside rules they themselves have to live by. Yep, that's going to work and engender sympathy. My people had their land stolen from them, were raped, robbed and pillaged into near oblivion by white settlers. Therefore, I should be able to live there now and do whatever I please. 
'PigletJohn, Travellers don't pay mortgages or rent. They pay cash. They don't want to rent from a bank or from a LA. They are willing to pay for whatever accommodation they live in. They don't want other people's houses or land. They want to buy their own and live in houses they build and own. It's the American Dream.'
Then why set up illegal sites on which they don't pay for their accommodation? This isn't America. They want that 'dream', they're as free as anyone else to get a degree/profession to get a visa to go there, marry an American to get a spouse visa, get a job to buy a plot of land on which they can legally build a home and live in.
You want it, you go out there and get it by earning, you don't expect people to hand it to you on a plate just because you don't like how they live.