When the Prius first got popular the same thing was said about it. Was soon proved false.
Yes and no. If you compare it to a regular car running on USA Gas, then yes, without a doubt. However, if you compare it to a car running on, say, Brazilian ethanol, the studies are still inconclusive.
My point is that most studies are valid under a given set of conditions, and we need to take those into account. If we make a case for the Tesla S polluting more, shouldn't we tackle the issue that energy production needs to pollute less? Alternative energy generation, better battery technology, those are the things we should focus on. So, if they are wrong about how much the Tesla S pollutes, we (the planet) win. And if they are right, they are still wrong, because their proposed solution, which is pretty much turning back time, is wrong.