why do babies count in carpool lanes?

I'm sure someone will be annoyed at me, well would be if anyone outside of my 3 friends read my blog, but why exactly is it okay to use the carpool lane if you have a kid in your car? I thought the whole reason we got carpool lanes was to reduce the number of cars on the road. So am I to understand that if mom wasn't driving little 2 yr old Johnny around with her to the store etc, he'd be out in his own car adding to the pollution? I fail to see how anyone under the legal driving age should qualify for carpool privileges. Seriously, even if you are hauling other peoples kids around with your own, their parents are still on the road in their own car going somewhere else. Having kids in cars does nothing to reduce the number of cars on the road and I do not think it should be a free pass to use the carpool lane. If they get to, then my dogs should qualify. They are unable to transport themsleves around but are still taking up a seat in my car, breathing air unlike the carpool dummies. Just my opinion but I'm sticking with it.