How do you add up the idea that HEV, PHEV, and EV cause as much CO2 as gasoline-powered cars? I do not see it. I think it is a pure line of....

They don't. Well, at least EV's don't. That's clearly a pure line of elipses.

The others have ICE's in them, so it really comes down to how they are used. Theoretically one could cause as much CO2 as an ICE car. If you have a PHEV and never charge it ever ever ever (to use an unlikely example), it will burn just as much gas as an ICE, so by definition it's the same effect. More, perhaps, because the battery is heavy and reduces fuel economy and generates emissions to build it, it might even burn more.

But as a general matter, that's kind of ridiculous. As a vehicle class, HEV's and PHEV's will generally generate fewer emissions over the course of average use by average users across electricity sources. In a very extreme case - a vehicle that's driven a lot on gas and not electrons, in a state where nearly all electrons come from fossil fuel, in an inefficient vehicle that generates a lot of CO2 to build, you might approach an instance where the CO2 was close. But not as a general matter.