[All of this is a simplification, and I'm omitting a lot here. The gist ought to be correct, and, I hope, fair to all.]

There are certain cultural barriers when it comes to the Roma. When you have an itinerant population like the Roma (and in Ireland and the UK, Travellers), you will naturally end up with with a conflict of some kind between the settled and travelling populations in a given area, unless both populations are familiar with one another, and even then the opportunities for discrimination are huge. The situation with Travellers in Ireland and the UK isn't as bad as the Roma situation, as the itinerant Roma population is self-isolating and can't speak the same language as the host settled population, whereas at least Travellers can speak the same language, so they're not as isolated from the settled population as the Roma are.

With Travellers, the core issue is that the trades that once allowed them to afford their lifestyle are no longer useful to society at large, so their opportunities for employment are few and far between, which unfortunately leads a greater number down the path of criminality [aside: the vast majority are decent people, but when you're deprived of opportunities, that's going to lead some people to crime]. Add to this that the modern state practically demands a settled lifestyle for things like taxation, education, healthcare, &c., which even further alienates the Traveller and settled populations. Now, you could suggest that they just settle, and some do, but people tend to be attached to their heritage, so for many that's not a runner.

With the Roma, all of that is even worse because they have the added language barrier and an even bigger cultural barrier. Moreover, you also have a trafficking problem surrounding some of the Roma where they're exploited as beggars, and sometimes worse.

So yes, the Roma situation is a completely separate situation from that of homelessness in general, and one nobody has any good answers for yet.