Surah Al- Maa'idah, ayat 75

I just read this surat and I came across some ayats I didn't understand. So I hope I can get a clear answer from you. > *The Messiah, son of Mary, was not but a messenger; [other] messengers have passed on before him. And his mother was a supporter of truth. They both used to eat food. Look how We make clear to them the signs; then look how they are deluded.* Who is meant by "they"(christians?)? The first thought that crossed my mind was Maryam (A.S.) and 'Isa (A.S.) but that can't be right because that wouldn't make any sense whatsoever. So does "they" refer to the disbelievers? In ayat 73 of this surah non-believers were mentioned and that would be the most reasonable explanation for the reference but I'm not sure. Can someone confirm or defend their own view of this ayat?