I first heard it from a TV character Old Christine who is an extreme Lefty and claimed, after being accused, that she ‘couldn’t possibly be a racist because I drive a Prius.’
What she was saying was that she is always PC in everything. What the audience heard was that she was morally self-righteous and had achieved such heights of properness with her Prius that she could do no wrong in any other area.
I expect to see and hear a lot more moral equivalence. ‘I called the INS on my maid after she broke a lamp, I like long showers and occasionally throw beer bottles out the car window… I’d better buy a Prius.