Iam I respect your input in such matters because you have had through your career an insight into working with different demographics that the casual observer lacks and we can only go on how local communities have often been affected by travellers. Who as you say do paint themselves as "victims" whilst behaving badly. Maybe they're just the bad eggs that besmirch the rest who don't behave in such a way, but unfortunately we don't hear about them it's the notoriety of the others. I can't remember where I heard this but I believe many emanate from Ireland where they're not tolerated as much as they are here in England.
What is noticeable quite often is the detritus they leave behind the worst of it is excrement and used baby nappies strewn all over the place. Then the local council have to clean that up at a cost to the local tax payer.
They appear to do what they like without repercussions. Intimidating locals. Parking on private property, sometimes concreting over fields without permission cutting through wire and locks to access playgrounds other specific community areas. Stealing from local shops, abusing shop staff. Where I used to live in a close outlying village, a popular Indian couple run the village shop/post office who had some teen boys come in steal stuff and when they tried to apprehend them they got a mouthful of racial abuse. It seems that one of the joyriders in this latest case is on trial for racially abusing and assaulting officers, I don't know whether he was from a travelling community or not. In the same village as the post office incident, I knew someone who lived there, residents got excrement chucked into gardens, even a dead dog! I'm afraid these behaviours do not endear them to local communities and using the "victim" card is very disingenuous. Residents are intimidated and often fear them, they ruin lives and cause an enormous amount of stress and when they clear off they leave a load of rubbish behind them.
Suffice to say, whoever the tearaway drivers were in this appalling and needless loss of life, my sympathies lie with the two officers and their families.