"Why do you care about morality? You're not a Christian!" This is what struck me, too. We live in a country where Christianity is the default religion and generally considered to be morally superior to other religions, as well as superior to atheism.
I remember when talk show host Donny Deutsch interviewed conservative media pundit Ann Coulter, and Coulter told Deutsch that all Americans ought to be Christian. Of course, Coulter thinks she's a comedian (she isn't, she's just a troll), so Deutsch questioned her further on what she had said to make certain that she wasn't being facetious (she wasn't). She continued to say to Deutsch (who is Jewish) that "We [Christians] just want [you] Jews to be perfected [like us Christians]."
Speaking as an imperfect Jew, I think that the uncaring, self-proclaimed Christian woman described in the OP represents a bigger problem with this country than any homeless people do. I certainly didn't see anything morally superior in her remarks.