rd: The Meiri and the Rama come for entirely different reasons. The Meiri on this is probably the most minority Shittah in existence (he holds that Hinduism isn’t Avodah Zarah) and the Rama didn’t have the Sefer HaYashar so he didn’t know what Rabbeinu Tam’s Shittah actually was.
Unitarians aren’t Ovdei Avodah Zarah. There are very few Unitarians. All Catholics are Trinitarians, as are most Protestants. Did you make sure that only Unitarians were at this soup kitchen, though?