Aine - thank you for the very interesting insight to the Irish version of the song. The "itinerant farmworker" here would probably be equated with "migrants" (los migrantes?) which would have about the same pejorative content as "gypsies" seems to have in Europe. There was a time when those low paid, unskilled jobs were filled by hungry "anglos", but in today's world they have largely been replaced or displaced by other groups.
As a kid growing up in the American mid-west, I heard the stories about "a Gypsy" took this, that, or the other thing or person, whatever or whoever happened to turn up missing. But I don't recall any of the kids giving voice to negative views about "Gypsies." Mostly, I recall that we romanticised them as care-free adventurers and wanderers, going where they wanted when they wanted. "Travellers" in a more literal sense of the word. Ah, for the youthful fantasy of freedom without responsibility.
Although there are gypsy groups here, I suspect that the antipathy of the adults of my youth was probably a hand-me-down brought over by previous generations from Europe. It appears to be what is called a "folk-way".
I can also see the bases for the interpretations GaryT and Soph have suggested, and though phrased differently, I think views expressed by Animaterra and Bob are essentially the same.
Do we have any Romas or Roma descendants in the family who might offer a view of the song?