Sad how people can't mind their business these days...
I had a similar situation at my university residence parking lot a year ago with my truck, (a '90 Sierra 6.2L)
I'm loading up the truck box with my belongings when this hippy dippy girl wearing hemp all over and barefoot (I kid you not... I go to a kinda lefty, liberal school with aging hippies and young ones ) and her granola boyfriend pass by. Without my making any eye contact whatsoever to either of them, she comes up and states that my "Gas Guzzler" is detrimental for the environment and wastes resources. She points to her late model Civic hatch (she drives her b.f. around ) and looks at me as if I'm stupid and says that her car is more efficient and "sensitive" for the environment. All the while I have this face :
After her spiel, it's my turn to rebut. Since I can be Captain Misogyny, I tell her that if she showered and changed clothes, the trees she walked next to wouldn't die; that if she washed her hair, it'd clog storm drains, and that she was a stupid who should mind her own business and invest in Borax because no soap could remove the smell. I also tell her that her guys' B.O. is the reason that banning CFC's still hasn't stopped the Ozone Layer from depleting.
I finished with "Make like an endangered species and off"
Knowing her guy couldn't take Woody Allen in a fistfight and she was pretty baked, I just stood there waiting for a reply. They leave to her car, and I go back to my business, they way it should have been.
If Irony comes in play here, it's when I overhear her saying that there's not enough space to fit all their stuff and that they'll have to do two trips, thus wasting more fuel and adding more pollution that I would.