Usually, when you point this out to someone, they will counter with "well, they pollute less." Which is only true if you're talking about specific pollutants, or comparing with a substantially different vehicle.
Take a Prius, remove all the hybrid gear, and it would likely get better fuel economy (thus less pollutants) overally.
The little 'greenie' mobile has to get its plastic, steel, aluminum and other materials from the same kind of factories that supply materials for 'regular' cars so the factories aren't polluting any less by supplying parts for the hybrid than for any other type of vehicle, right?
About a Corolla if you take out the big batteries etc isn't it ?
It would be a stretch for you to prove your point bu t let's just leave it with 'It would not have enough power to get out of it's own way ...'
Take a Prius, remove all the hybrid gear, and it would likely get better fuel economy (thus less pollutants) overally.
Take a Prius, remove all the hybrid gear, and you have an Echo.