It should be noted it's comparing the claim vs the cars actual co2 output, which for PHEV is laughably incorrect in real world use. I'm amazed a class action hasn't been made againts these car companies. They knew what they were doing and its nothing short of environmental terrorism levels of deceit.
That said, Plug in hybrids are still 'better' than petrol or diesil cars for overall emissions. The title makes out they're worse. Which is untrue.