This person was not a Samaritan, a proper noun meaning a person from Samaria. This person was a samaritan, "one who is compassionate or helpful to a person in distress", a common English noun derived from the story of the good Samaritan that you are referencing. When we use the word samaritan, we are specifically trying to evoke the idea of that one good Samaritan. So yes, your point is technically correct, but not relevant.